There are 5 common playable 2/3s. I don't want to be playing aggro in this format. Evasion will be at a premium. The low number of 4+ toughness commons means that 3/xs, lightning strike, and crowd's favor are all very good. Forge devil kills a lot of stuff. Invasive species is an aggro card because it bounces lands 90% of the time. More insights later.

Not much unconditional removal. 5 colors of walls.

I think the paragons might be pretty important.

How many 3/3 there are? Maybe it's just a format for them like return to ravnica.

Invasive Species, Scrapyard Mongrel, and Flying Snidd are the only common playable 3/3s in the set. The only common playable wall is Coral Barrier.

Is Wall of Fire not playable? It's a pretty insane blocker.

I think I agree with you Cato about how this format will not be aggressive just because there are so many random walls and things that blocks pikers.

Also, Restock at Uncommon is pretty insane and I think that should be pointed out.

The problem with wall of fire is that it's red and doesn't attack.

I played 2 drafts with Tyler. The way the format works is that the board stalls out, then whoever is the first to play a legitimate threat that doesn't get removed wins.
Legitimate threats include:
-anything evasive. The board stalls out hard.
-anything 4/4 or bigger. Really, creatures are all tiny in this format.

We drafted b/g both times, and I think it's the best color combination in the format because it gives you threats, removal, and enough midgame to keep the aggro decks down. You want to play a couple midrange durdles (spider, necromancer's assistant, satyr wayfinder, Living Totem) to buy time, drop a threat (Accursed Spirit, Siege Wurm, Willforged Golem, Carrion Crow, Charging Rhino), and ride it to victory while using flesh to dust, hunt the weak, necrobite, typhoid rats, and covenant of blood to kill their threats. Also, I learned that convoke is stupid overpowered. You can just drop a turn 4 golem or turn 5 wurm and ride it to victory, and covenant of blood is premium removal.

TL;DR
-Boardstalls are the norm
-All the creatures are tiny
-All that matters is playing evasive/big guys and killing your opponent's evasive/big guys
-If it has convoke in the rules text, it's probably overpowered.

I'm waiting for the set to hit Gatherer and/or MtGO, but that common Spider really looks good. As do the Rats. Ancient Silverback at uncommon seems dangerous. If this really is so slow, then Jace's Ingenuity and/or Brawler's Plate could be good. And there seems to be a lot of life gain.

walls + convoke? Is that a thing?
Satry Wayfinder is a midrange durdle?

slightly OT but how do you organize drafts on drafts.in? Just create one and send around the link?

Satyr Wayfinder is good because it trades with pikers and gets you lands so you can play your wincons and removal spells, you don't need walls to convoke with, you just need any 2 or 3 drop creatures, spider is really good because its 2/3 body stops aggro and its 4/3 antiflying body can effectively be removal against fliers, and jace's ingenuity is bad because it's in blue and blue is an aggro color. Also, yes, that's how you use drafts.in.

Hey, when aggro runs out of gas, guess what? It refuels with Ingenuity! But really, is blue aggro in M15? I think I'd enjoy that.

It's a bit schizophrenic. There are some cards that only work in slow decks (looter, coral barrier, flying snidd) and some that only work in fast decks (welkin tern, frost lynx, bounce, amphin noblox), but I think there are more aggro cards than there are control cards. I also think the divisiveness limits it as a color, because either deck will only get to play half the cards.

Is this an 18 land set? 6 drops ahoy?

Nah, all the expensive stuff has convoke anyways.

I'm playing two sealed events at the prerelease this weekend; 1v1 and 2HG. Give me a rundown of the powerful "sleeper" cards (i.e. those that newer players would overlook).

Well, the most important cards are finishers and creatures that can deal with finishers, so get those. Some overlooked finishers and antifinishers are:

-Netcaster Spider: It's big enough to kill pretty much any flier you need dead, and stopping evasion is really important this set.
-Covenant of blood: this is easier to cast than it looks, and it kills almost everything in the set.
-Will-Forged Golem: By this set's standard, it's really big, and surprisingly easy to cast.
-Typhoid rats: removal is at a premium this set, and this is removal.
-Crowd's favor: due to the lack of fatties in this set, this will help you win a lot of combat.
-Necrobite: removal is crucial.
-Amphin Pathmage: the set is slow enough that this is actually good.
-Triplicate Spirits: evasion and convoke are both really good in this set.
-Satyr Wayfinder: there are a good number of x/1s in the set.

Just looking over the full spoiler and am interested in hearing what you think of these cards:

Feral Incarnation
Glacial Crasher
Undergrowth Scavenger
Research Assistant
Caustic Tar
Xathrid Slyblade
Zof Shade

I think I agree with you about Convoke cards; a lot of them seem really strong.

Incarnation is great. Boards stall out so frequently, especially with green decks, and there are so few 4 toughness guys that each of the tokens should trade for a card.
Glacial crasher is a blue/red card, but blue/red is an aggro deck, and you already have 2 6 drops in red, so even if you wanted a curve topper, this has competition.
Undergrowth scavenger just seems bad. You can't play it early game, and even if the board stalls out and the game goes long, that means guys won't usually be trading. I guess it has some synergy with self-mill, but that isn't enough to make up for its overwhelming mediocrity.
Research Assistant's body is nice, there are a lot of 2 power guys and 1 toughness guys, and looting is nice in long games, but it means going into a blue control deck, which I'm a bit skeptical about.
Caustic tar is great inevitability. I'd play it in most black decks.
Ditto for Xathrid Slyblade
Zof shade is kinda the same, but you need to realize when you play it that it isn't a 4 drop, it's like a 5 or 6 drop, because it does pretty much nothing when you play it on curve, and it's one of the worse options for the "finisher" slot. Still, if you don't have many ways to close out a game, it's fine I guess.

Just voicing my opinion, white seems really good in M15. A lot of the rares/mythics are massive "must deal with this immediately" threats, and the common/uncommon pool is no slouch either.

The problem with white is that it's an aggro color and I don't like aggro in m15.

Also I made a spreadsheet of all the m15 playable common creatures by color, cmc, and whether they were aggro cards, control cards, or both.