I think it's because you are building your Wizard as only an AOE caster that you find their spell selection lacking.
Wizards also boasts the best self-buffs in the game compared to the other casters (only the Priest even comes close and you're better off just using those buffs on your tank anyway) and can stay at a consistent level of effectiveness throughout the game instead of sucking early on then becomes great once level 9 hits like the Priest or the Druid or blowing through their focus early on in the fight like the Cipher.
Instead of just focusing on AOE, how about you try using a Kalanoth's Minor Blights build? Coupled with Eldritch Aim, Deleterious Alacrity of Motion and Citzal's Martial Power, my Wizard turns into an auto-attacking beast who even out-damages my Rogue during long fights (esp. the dragon fights, who has an insane amount of Deflection)