I'm sort of in the same boat. I've been playing a white mage since launch, but want to try a DPS class for a change of pace (also, there seem to be waaay too many healers for some reason).

My main limitation is that I'm playing with high (250-300) latency... so any class that relies on precise timing, tight burst windows and/or double weaving is probably out. I have summoner leveled up fairly high, and it seems to be OK... but how about other classes?