Quote from Drat3r
The first inferno Diablo kill was with a wizard.. I can't see how he's underpowered.
Bosses hit very hard, but also relatively slow since its just one mob. This means that Energy Armor w/ Force Armor is super effective vs bosses. You can find Youtube videos of wizards tanking inferno bosses with 7k hp (less hp actually makes Force Armor even better). So for boss fights wizards are the strongest of all the classes. However that doesn't mean the wizard is amazing in every aspect of the game.
I'm not saying wizards are underpowered/overpowered. I'm just warning against making a judgement call based on boss kills because right now Force Armor makes wizards gods vs bosses.