SSB, set size, and Card Frequency
In triple BFZ, Commons appeared 2.38 per draft, Uncommons at .9 per draft, Rares at .40 per draft, and Mythics at .2 per draft.
Now, BFZ Commons are .79 per draft, Uncommons .3 per draft, Rares .13 per draft, Mythics .067 per draft.
Contrast that with OGW Commons at 2.25 per draft, Uncommons at .8 per draft, Rares .34 per draft, and Mythics .17 per draft.
The reason for this, of course, is that OGW has many fewer cards at each rarity than BFZ AND there are twice as many packs of OGW.
The takeaways are that, if you're looking for a particular OGW card, it's going to show up just a little less than a card of equal rarity did in triple BFZ, and, more important, any particular BFZ card is going to be very unreliable to show up. In fact, it's like all the BFZ cards just got up-shifted a rarity (actually they're slightly rarer than that, even). So for instance, any particular Uncommon in BFZ is less likely to show up than any particular Rare from OGW.
Old Synergies Washed Away With Sea Gate
Triple BFZ was generally known to be a pretty synergistic format (though there were some who debated how much this was true). The new format will demonstrably be very very different. Most of the themes of BFZ are supported little to none here. There's 1 life-gain-matters card (an uncommon), absolutely no Processors, no ingesters (though some exile still), and no Awaken (though a few land-creatures), with only two lonely instances of Landfall, and no Converge at all.
Devoid is one theme which survived and actually increased (in a way). The mostly RB mechanic of caring about when colorless spells were cast or having colorless creatures in play didn't get entirely axed, though it is somewhat less prevalent than it was before - a BFZ pack had about 50% more of this stuff than an OGW pack, meaning the draft will now have a bit over 75% as much as it did before.
Scions are still around, but there are MUCH fewer of them than there were before. In triple BFZ, we could expect about 19 Scion-producing cards opened per draft. Now we're down to only 13 - and half of these, of course, are from the single pack of BFZ that's still around.
The big news, of course, though, is actual factual colorless mana. Not the old 'true colorless' a la Ulamog, but the 'MUST be colorless' of the new Kozilek. The cards with C in their casting cost are all at higher rarities, meaning you only expect to have a bit over 4 opened per draft. However, There are quite a few cards with colorless-required activations: about 24 per draft. These are most frequent in Black, closely followed by Blue; Red and Green clock in at about half of these other two (and White has a lone rare).
In terms of Colorless sources, we're looking at, as mentioned above, about 13 scion-producers per draft, along with about 27 other sources (mostly lands, with a couple artifacts, and a few creatures), for a total of just over 40 colorless sources - and this isn't counting basic-searchers as extra sources (which of course would only work for one of the approximately 4.5 actual factual Wastes per draft). Scions are disproportionately in the BFZ pack, but the other sources are far-and-away more likely in the OGW packs, and that's the lion's share of your chances to get one. This is also worth keeping in mind when you're thinking about whether you need repeated sources of colorless (for repeated activations), or just a one shot (from a cast or ETB trigger or in an actual casting cost). 40 is quite a significant number of sources - split amongst 8 players gets you to about 5 per player per draft, but we can expect some players to have no need for them at all. This is certainly enough for every single player to be able to 'splash colorless', and actually even for a couple players to have it as a 'main color'. The actual effects seem to mean to me that this doesn't really make much sense, but it's good to know that, if you want it, it shouldn't be that hard to get 6 sources for quite a heavy splash. The bigger takeaway is that you probably don't need to prioritize these kinds of cards, they'll be plentiful enough.
A quick note on Wastes: I would try to avoid them, generally. There's a few cards which care about them specifically, but the payoff isn't so great, and then there's also a few which can search out a basic, which make the first one far more valuable than the second, but I wouldn't really be looking for that first one anyway.
Very related to the subject of Colorless is that of mana fixing. Many of the colorless sources indeed do both - Unknown Shores, for instance, has never looked quite so good. The amount of fixing overall is way way up - an increase of over 50%. We're now looking at 20.6 cards, on average, of fixing per draft. This is largely the result of a few mediocre commons as well as an uncommon cycle of tap-lands. This really isn't enough for everyone to go three-colors, especially with wanting to splash Colorless and some of these being inefficiently distributed to people who can't use the colors they provide. Having said that, it certainly makes going for 3 colors much more of a possibility if you want it, and 4 or 5 (with colorless, 6?!) colors not completely crazy if you really want to go deep (not that I would recommend it). However, I do expect that most decks now are going to be able to run 2 and a splash (whether that be for a normal color or colorless or, if it's very light, perhaps both) if there is much reason at all for them to do so. Just remember that you need to get that fixing in from your first couple packs, because by the time pack 3 rolls around, it drops down rather significantly.
A last note here is that 20.6 cards is just a smidge over 2/3 of the fixing which came from lands in triple KTK. I think this goes pretty well to support my point of 2-with-a-splash being common. But we'll see - a lot has to do with the payoff.
One of the defining features of triple BFZ was that it had a lot of mana sinks. This gives you things to do with your lands, provides flood insurance, is some inherent form of Card Advantage, and I think generally led to a very big chunk of why the format was liked by the players who liked it - generally I've heard people talk about liking the gameplay more than the drafting (which makes sense given that roughly half the archetypes were close to unplayably bad). Overall, we were looking at about 33 mana sink cards per draft in triple BFZ. Now, we have even more, all the way up to 40. However, it's worth noting that a big majority of the new sinks, and indeed a slight majority overall, specifically require colorless mana. So the number of non-colorless sinks is slightly down. Given that I think many, if not most decks are going to want to play a few colorless sources, this probably isn't a big detraction. However, it is something to keep in mind. If you end up not getting or going for those colorless sources, the other mana sinks are going to be at a premium, and those are largely in the third pack.
Of course, Kozilek and company aren't the only theme of the set. It's also about a bunch of super-friends forming a pact to save the multiverse.... which isn't really going to have any impact on limited at all. Yes, there are some "Planeswalker matters" cards, but they tend to be at rare, and anyway you're unlikely to have a Planeswalker, or especially a 'walker and a card that cares about that. Still, there are other themes from the non-colorless folks (yes, this sounds like a bunch of verbal gymnastics, but think about it for a second...).
Allies are back, and actually in slightly increased density from triple BFZ. There is a BIG difference in how they're going to play, though - Rally was essentially "ally-fall", meaning bonuses for ETB, which on something that happens at sorcery speed, means that you're going to have an aggressive bent to those abilities, in general, and BFZ was no exception to that. It didn't really come together, though, and I think that's largely down to most of the bonuses just being too lousy. The big ones were the green team-pumpers, but green was awful, there weren't many of these, and they were very expensive. Beyond that, double strike was good, and menace was ok, but the pickings overall were pretty slim. Vigilance? Color me meh.
Anyway, this time, we have Cohort. This is a huge huge huge huge change. Cohort requires you tapping two of your creatures, and you can do it at instant speed. This means that it's really going to be a defensive ability - you can both block (or at least threaten it) and activate your Cohort, but you have to choose between activating and attacking. Several of the abilities also promote this control theme. I really think this is going to be something people miss for quite a while - they will assume "allies is the aggro deck", but it most certainly is not.
Ok, so that wasn't really based on the numbers, but there is some math to be done here. First off, how much Cohort is there? A bit over 13 such cards per draft, which is slightly less than the amount of Rally from triple BFZ. If we bear in mind that maybe half the table isn't going to be on Allies basically at all, this leads us to something like 3 to 6 Support cards per Ally drafter, on average, though obviously a lot depends on a number of different factors. How many allies are there to support this? Well, a lot - over 54 per draft, meaning that anyone who is playing Allies should generally be able to get plenty to be able to activate their cohort abilities as long as they can actually get their creatures down (curve) and have them survive. It's also worth noting there's still some Rally floating around, just not that much (and of course, much of it isn't that good).
Then we get Support. Support adds +1/+1 counters to creatures (if it's on a creature itself, they have to go to OTHER creatures). There isn't really that much theme to this, or critical mass - yes, there are a few cards that reference the counters (focused mostly in green), but only a few per draft, so it's not something you should be counting on really. What we DO need for Support to work out are creatures in play to support on. For the record, almost all of the Support in the set is Support 2 - we have one uncommon that gives 3, and one rare that's 6, but the rest are 2. In order to maximize value, that means we need 2 creatures in play. That means we need cheap creatures (and/or changing the order in which we play our cards). How many cheap creatures are there in the set? On an average, per-draft basis, 8.6 1-drops, 41.5 2-drops, 51.0 3-drops, 39.5 4-drops, and we're not talking 'cheap' anymore.
Actually calculating the exact chances for whether or not you hit your curve-out start to be able to get to fully enabling your Suppport 2 by turn N are extremely complicated, as it depends on how many creatures you have at every slot on your curve, how many lands you have, whether your colors are in line or not, whether you're on the play or draw, how you mulligan, etc etc. However, if we make several simplifying assumptions and apply some hypergeometric math, we can get a (very) rough picture of how likely your Support N cards are to being "on" on curve.
For a card like Shoulder to Shoulder, assuming you have it in hand, if we ignore needing lands and mulligans, you're a slight favorite to have it 'on' turn 4 on the play, and a significant favorite on the draw. If we factor having enough lands, you're an underdog on the play and right about even money to get there on the draw. Mulligans probably increase these probabilities very slightly (since you're going to mulligan the low-landers). Realistically, because of things like color-screw and opponent's removal, I would guess that you would be more likely to have about a 1/3 chance to actually get the dream draw here on the play (ok, not the real dream of 1-drop, 2-drop), and a bit closer to 40% on the draw, again assuming that you drew the Shoulder to Shoulder to start with. I imagine that if you get this draw, the card is great, but of course, this is a somewhat unlikely (though not at all unheard of, especially if you draft more cheap creatures) scenario. In a more typical deck, I expect the card to be somewhere between mediocre to fine.
Once you move up to more expensive cards a la Expedition Raptor, the chance that you'll have had enough cheaper creatures goes up quite high, but of course, you're fairly unlikely to have all the land drops on time to actually play the Raptor on curve. More specifically, you're unlikely to have both the creatures to turn a card like this on as well as the lands to play this on curve. By the time you do actually play this card, you're going to be pretty likely to enable it, but of course it's not going to be what you're looking for in a flood.
There are a couple things to note about Support in general. First, you want lots of creatures, and generally cheap ones. Second, the counters get pseudo-haste. Third, it seems very likely that you will at least be able to half-enable the Support; doing more than that is possible but will require some amount of work, or not getting there as "on-curve" as you'd like.
Surge is another mechanic that encourages you to play cheap cards. Once you add in all spells, you're up to a per-draft average of 17.4 1-CMC spells, 55.1 at 2-CMC, 61.6 at 3-CMC, plus Bone Saw. There are just over 14 cards per-draft with Surge, all in Blue and Red. Thus, if you're in one of these colors, you're probably looking at roughly 2 such cards, assuming they're good enough to make the cut (if you're in both colors, it looks closer to 4). That probably isn't really enough to draft around. The (rarity-weighted) average cost-reduction is 1.85-worth of CMC. Basically, this means you shouldn't really be holding things back in order to enable surge later on (with the possible exception of some of the cards like Crush of Tentacles that give you a bonus when surged). Also, you're going to generally want 2-drops (or the 1 CMC cantrips, or one of the few good 1 CMC other spells) in order to do your enabling. Verdict: nice, but don't go out of your way; there is no surge deck.
- Processors are down from 20.2 per draft to 1/3 of that, 6.8.
- Ingest is similarly down, but other exile effects are only marginally down compared to before.
- Awaken drops from 59.6 cards per draft to 19.8, though there are an additional 4.5 awaken-like cards in an uncommon cycle from OGW. The awaken that is there should be better now (because it's more scarce), but cards like Halimar Tidecaller should be worse.
- The Life-gain deck is gone. Down from 10.2 cards that care about it to 4.2, and from 17.6 actual life gain cards to 12.0 (many of which are green now).
- The Equipment theme is also not really a thing - only 4.2 cards that care about it per draft, 5.6 actual equipment, and many of these cards don't really look very good anyway.
- Converge should be easier to grab, but on the other hand, you really can't count on any payoff, so it's not something you should really be looking for.
I'll be back soon with more on creature size, removal, and maybe colors soon.