I think hunter is very easy to do well on, but I'm a very experienced player so my point of view may be skewed. In BGs, if you're not concerned with pulling off awesome CC chains, it's basically 3-4 abilities and you never have to stop running.
Other considerations for BGs would be: elemental shaman, destro/demo lock. Just don't expect to easily defeat melee that get on you. Ret paladin isn't terribly complicated either.
I would NOT recommend: any druid spec (very fun but not basic at all), shadow priest, or enhancement shaman (unless you enjoy turbo burst every 3 minutes and being kited for the rest of the time)