Druids excel in herb gathering.
However, they cannot mine in flight form. That means that if someone attacks you in mining form, you cannot fly away from damage since you cannot go in flight form in combat.
I'd say Paladin tanks make the best miners, Paladin because of the Crusader Aura (you beat competitors to nodes) and because if someone attacks you over a node, I'd rather be a tank and annoy the shit out of them.
Hunters also rock for stealing nodes. If you see someone farming a node, ice trap him, gather that node and fly away