This started out as a post in Arena Genereal, but then I decided it was long enough that it warranted its own thread. I then, of course, made it longer, but I hope it's worth reading.
Arena Pre-GvG
Before GvG, the game was something like this:
1. Pick Rogue, Mage, Druid, or Paladin -- Warrior if you must
2. Draft good class cards and lots of Raptors.
3. Don't make dumb plays.
4. Profit.
It really was that simple. Just doing that probably got you 80% of the way to optimal play.
Basically, the idea is that if you win the first 4 turns, most of the time you're going to win the game. Of course, there can be some major swings late in the game with the strong class cards, but assuming you have similar deck quality, having the upper hand after turn 4 went a long way toward securing the win. If you had the tempo advantage when you threw out your first good big guy (like Merc or Spectral), your opponent was going to have a hell of a time dealing with it, much less overcoming the inital tempo disadvantage.
So how do you win the first 4 turns? Mostly by having enough Raptors. If on any of the first 3 turns you could play a 2-drop while your opponent couldn't, you'd be ahead. And if they didn't have a game-swinging 3-4 drop (Senjin, Yeti, Crusader, Harvest Golem, Twilight Drake, or class stuff like Truesilver, Death's Bite, Water Ele, Multi-shot, Frothing, Unbound...), you really had your back to the wall. And there were only 4 neutral commons that fit this bill-- Sen'jin, Yeti, Crusader, Harvest Golem. Raptors could trade up with 3-health 3-drops, and with a ping hero power could trade evenly with 4 health 4-drops.
So you wanted to have enough 2-drops that you didn't get run over early, and you really couldn't have too many Raptors since they traded pretty decently with almost anything. What did this add up to? Drafting Raptors was a pretty solid thing to be doing most of the time.
Here's a first-order approximate list of draft priorities:
1. Game-swinging 3-4 drops (Sen'jin, Yeti, Crusader, Harvest Golem, and Dwarf (which lets you trade Raptors up for Sen'jin/Yeti))
2. Top tier big guys (Boulderfist, Merc, Spectral, Tiger, Champ) to close out the game
3. Good situational/utility cards (Ooze, Cult Master, Cleric, Inventor, Spellbreaker, Farseer)
4. Good 1-drops (Chow, Infiltrator)
5. Good/decent 2-drops (Amani, Bomber, Panda, Loot, Dire Wolf, Faerie Dragon, Raptor, Bluegill, Unstable Ghoul, Creeper, Bloodsail Raider, Croc) and second-tier 5 drops (Silver Hand, Warlord), Raging Worgen
6. Third tier 4+ drops (Smith, Fen Creeper, Commando, Big Panda, Stormwind Knight, Frost Ele, War Golem) and Abusive Sergeant
7. Third tier 3-drops (Wolfrider, Acolyte, Flesheating Ghoul, Grizzly, Razorfen, Panther)
8. Weak stuff, depends on your deck.
This is only a rough outline, and there were some shifts depending on your class and what rares you end up with, but for a first-order approximation, this is pretty close to what you wanted to be doing.
Notice there are only 18 cards that were significantly better than Raptor. (Yeah Bomber is strictly better, but often just did the same thing.) That's 18 neutral commons out of 87, just over 20%!
So what changed with GvG?
1. There's way more stuff that can 2-for-1 Raptors.
2. There's way more playable 2-drops.
Shredder, Mech Yeti, Spider, and Brute all join the top tier, nearly doubling its size. Plus there are a couple rare 2/4 3-drops (Sapper, Illuminator).
The new playable 2-drops are Annoy-o-tron, Sheep, Gilbin, Mechwarper, Micro Machine, Puddlestomper, Ship's Cannon, Stonesplitter, and one per class except Warrior (if you count Glaivezooka, which isn't really a minion). That's about a 67% increase.
But the total common card pool only grew by about 23% from 103=87+16(class) to 127=109+18(class).
Between these two factors, the importance of drafting Raptors has gone way down since:
1. It's easier to win the tempo on turn 3-4 rather even if you don't on turn 2.
2. There's so many 2-drops that if you find yourself short on them, it's not hard to catch up in the last few draft picks. It's of greater relative importance to draft the better high-end cards, since there was only ONE good 5+ drop added (Force Tank).
So draft-wise, it seems you want to bump up all the decent 5+ drops. And play-wise, the game is less likely to be decided by someone failing to draw their 2-drop. With the games going longer, classes with better high-end cards (Druid, Priest) or later-game hero powers (Warlock, Priest, Shaman, Paladin) get bumps relative to the better early-game hero powers (Rogue, Mage). Also, the increase in sticky minions makes buff cards better, and thus the classes with more buffs (Paladin, Shaman, Priest).
I haven't really figured out how all the classes stack up against each other yet, or what the right draft priorities are beyond the very top, but late game seems much more important than before, and Raptor seems much more like a vanilla card than an arena dominator like it was before.
For reference, my new priorities are something like this:
1. Game swinging 3-4 drops (Shredder, Mech Yeti, Yeti, Crusader, Spider, Brute, Dwarf, Sen'jin)
2. Top tier big guys (Boulderfist, Merc, Spectral, Tiger, Champ)
3. Harvest Golem (2 attack power makes it much weaker than the new top 3-drops) and stronger situational/utility stuff (Ooze, Cult Master, Cleric, Spellbreaker -- no Inventor for reasons similar to Harvest Golem, and no Farseer since there's more stuff that straight-up kills it for 3).
4. Second-tier 5-drops (Silver Hand, Warlord)
5. 1-drops (Chow, Infiltrator)
6. 2-drops with upside (Amani, Bomber, Panda, Dire Wolf, Micro Machine, Loot), third-tier 5+ drops (Smith, Fen, Commando, Frost Ele, Tank), and Inventor and Farseer.
Thoughts?