[spoiler]P1: Violet Teacher, besides being the obvious choice Shaman drafts you tend to end up with a bunch of cheap spells (Earth Shock, Bolt, Rockbiter) so it's a great card for the class.
p2: Faerie Dragon, 2 drops are very important, you will lose games because you weren't able to to have one on curve. It's also one of the better 2-drops.
p3: Darkscale Healer, healing tacked onto a body is good (has always been good even in Magic), Snapjaw is mediocre, War Golem is not needed this early.
p4: Dragonling Mechanic, it sucks but it's better than the rest. What it really says is 4 mana make a 2/4, your opponent overloads 2 mana next turn. Good with Bloodlust I guess. Shieldbearer is only good in aggressive decks and Magma Rager sucks.
p5: Fire Elemental, best common 6 drop in the game
p6: SSC, one of the best arena 3-drops. Obvious choice.
p7: Razorfen Hunter, choice is similar to Dragonling Mechanic. Lord of the Arena is okay, but the only 6-drops you want to be looking for are Fire Elementals and Boulderfist Ogres.
p8: Dwarf, one of the best arena minions in the game.
p9: Hex, single best removal spell in Arena. Deals with voltron and bombs.
p10: Azure Drake, best rare minion in arena.
p11: Murloc Tidehunter, picks are all bad, Tidehunter because it's a 2-drop and it has syngery with buffs
p12: Yeti, I don't think I have to explain this
p13: Gnomish, replaces it self, good with buffs, eats up 2-drops. Spellbreaker is overrated.
p14: Loot Hoarder, 2-drop, trades favorably with other 2-drops. Usually overloads the opponent 2 mana the following turn. Crocolisk is bad because arena is filled with too many 3/3s.
p15: Forked Lightning, lacking removal and good 2-drops, also good with Violet Teacher.
p16: Axe, early game removal
p17: Earth Shock, the reason why I didn't pick Spellbreaker. Great against Loot Hoarders, Scarlets, Twilight Drakes.
p18: Gnomish, I don't actually like having more than 1 Axes in my Shaman decks. Having 2 would make finding them earlier easier but the second Axe is so much worse than the first because of the amount of removal Shaman decks tend to have and how big the creatures tend to get in the later stages of the game.
p19: Rocketeer, 6-mana removal spell. 5 is a pretty important number in arena.
p20: Imp Master, curve needs more 3-drops, good with buffs and healing totem
p22: Silver Hand Knight, best common 5-drop, good with buffs, potentially Bloodlust
p23: Windspeaker, not enough spells to take Magi and Squire is not good in arena. Good with minions that have big butts, an out to draw if you have Rocketeer in hand with opponent at 10 life.
p24: Mad Bomber, one of the best 2-drops. Expected value makes the card good and you have control of when to play it. Good against Worgen Infiltrators.
p25: Frostwolf Warlord, good with hero power, good with Silver Hand Knight, Razorfen, Mechanic, etc.
p26: Harvest Golem, best common 3-drop in the game
p27: Earth Shock
p28: Kobold, 2-drop, has synergy with some spells but not that great. Better than tidehunter and the curve doesn't want another 4 drop.
p30: Azure Drake