Right, druids weren't super mobile at that time, no not at all. It wasn't the major reason for their dominance in Arena, no siree. You are right tho, I forgot mages, they have always had fun. But look at those 6 classes, all of them have high mobility either from active abilities like blink, vanish, sprint, charge, travel form, or by having a lot of powerful instant casts, PW:S, Renew, PoM, Druid Hots, Lock Dots. They all have strong survivability on their own with vanish, blind, gouge, poly, priest wings, fear, last stand, shieldwall, bear form, tree form. And they all have burst. If you didn't play one of those classes at the end of TBC, you didn't play arena. Also, no shadow priests, no holy priests, no fury warriors, no boomkin, no feral etc.