I've done 4 man mono-class teams. Shaman were the fastest if I could gear them out. Without gear, I had great success with both warlocks and mages.

Shaman - kill elites in dungeons. chain lightning, insta chain, earth shock -- usually enough to get most of a pull dead. Same deal in pvp, btw.

Warlocks - run around outside and throw dots at everything as you run by. Xp speed comes from never having to stop.

Fire mages (FIRE!) - pure glass cannons -- all spell power -- all specs into pyroblast, fireball, fire, fire, FIRE FIRE!!! I mostly fought with these outdoors. Again, never having to stop...find someplace where the mobs don't run out and it turns into non-stop xp.


Warlocks were by far the simplest, since they just run along and drop 1 or two dots each. You literally never need to stop. They are also fairly safe against world pvp since 8 dots (10 in your case) will wipe someone quickly. Additionally, they don't need to be facing whatever they are casting.

If you are geared out, I can't imagine anything better than a group of shaman wiping whole pulls at once in dungeons. The xp from this was insane. I never tried it without equipment provided by upper level characters, but I was also only using 4. No tanks or healers needed.

I'm weighing my options for vanilla and leaning toward doing warlocks again, myself, at least for the start, just due to the simplicity.