2. Not putting any points in Arcane Concentration. Not only does 1/10 spells you cast cost absolutely no mana (fantastic for a full stack of Arcane Blast or Arcane Missiles), but every time the talent activates you gain 30% crit on your next spell.
3. No one puts points in Student of the Mind. It's a terrible talent.
1. Slowing a Zombie Chow that gets missed by the AOE snare, Slowing Anub when the tank is circling the room... useless... most bosses in Naxx 25 can be slowed, thus a boss that needs to be kited around the room does less damage to the tank helping the healers... useless... got it.
2. 1/10 is not accurate. 30% increased crit is nice... and i think with your #3...
3. You are correct... working it out on paper and looking at other pages... your right... terrible points better spent in the Arcane Concentration.
I'll admit i'm a bit of a noob on this site. I'm consistently in the top 5 in damage, just working on the gear to get me to the top every time.