Im at like lv 8 and I still do not see the appeal of the wizzard. Yes hes got some AOE nukes, but I honestly use him more for hastes and slows rather than aoe nukes which are highly situational. Basically an opening barrage, but when the fight continues and my melee are in range of the mobs, he becomes rather useless other than his buffs/debuffs/catrips. At this point im wondering weather to change him out for another melee. Melee is just so strong in this game especially with the movement options like jump and the misty step or whatever items they have, movement is a non issue. Most are high AC/HP so they can stand a beating as well. And in a good round a melee can do 2x or more dmg to a mob than the wizzard can. Other than his int check dialogue BS, and some buff/debuff I honestly dont see a need for him. Plus I respecced my cleric to light cleric so she now has a couple of nukes herself.
Warlock I tried too and honestly hes a waste of spot. ZDPS, at least at my levels. Sure he can hex but is it really worth having him in group for a hex? Meh, I sidelined him a while ago with his 8-10hp IF HE HITS AT ALL hits.