I don't like the whole vehicle thing.
I'd rather play my class or classes, then push the 1-5 relevant buttons on a vehicle.

Blizzard is experimenting, Leviathon in Ulduar, vehicles throughout this expansion, mounted knights etc.
I hope they move away from this.

I pick a rogue, or shammy, or paladin, or druid etc.
To have hots, heroism, lightning bolt, holy shield etc.
I'd rather play my class, then be a tank, helicopter, mounted knight/horse etc.