Druids add a lot to a caster group's DPS. You get stacking mana regen, nuke aura, crit bonus from wolf form, cold/fire debuffs, and a big 25% bonus to nukes on named. Druid's are hard to run as an automated main healer though. They don't have the same spamable fast heals that sham/cleric get. If you run them as a back up healer and nuker, they are good though.
Monks are very good DPS, but they do run out of endurance pretty easy compared to melee like Zerk that barely sips their endurance pool. They are a little easier to automate than like a Rogue, that requires more conditions for chaining their burn cycle correctly.