So I'll say a controller perhaps? Anyway, play what you want, and what you like, the party is most balanced. I found that playing a character you don't like usually spoils the post rating. At least it happens to me.
Chizz is capable at range but gets more synergy in melee with a melee partner, so I'll greatly enjoy having a battlemind AND a paladin around. His daily stance relies on him getting attacked, so there will be times he doesn't want his foe marked.
We have a controller, a Druid... or does Taran tend to behave like a tank?
He favors beast powers, but he has to area at wills (one gives CA to us), one area and one multi-target encounter (one with status effect) and one summoning. So we should be fine on the controller side for handling minions, but not fully to 'penality-out' single targets.