Which class would best fill this last group spot?

[solleks]

Warrior - halfling ( tank )
Cleric - halfling ( main heals / roots cc / lulls / ivu)
Rogue - halfling ( dps / scouting / recovery )
Rogue - halfling ( dps / scouting / recovery )
Druid - halfling (back up heals / travel speed / pulling outdoors / charm dps / roots cc)
Druid - halfling (back up heals / travel speed / pulling outdoors / charm dps / roots cc)

[Polycaster]

I'd say 2 halfling warriors, 2 halfling rogues, 1 halfling cleric, 1 halfling druid.

This build has much better symmetry.