Well, I can't speak much to the level 70 game.

But mages.... as of around December 2006 - yes 2006.

Lifetime Honorable Kills: 81208

http://armory.worldofwarcraft.com/ch...heridon&n=Xzin

But don't expect to do this at level 70 in heroics or in arenas.

4 Warlocks 1 Priest and 4 Mages 1 Priest are still very viable in BGs and world PvP, including the up and coming Northrend "outdoor style" siege weapon non instanced PvP. In arenas though, cloth means you are squishy. When you have 5 people with all of their cooldowns and ultra high end gear, cloth isn't where you want to be. You want to be inside a siege tank. Which is where the shammys come in. Armor. Shields. Grounding Totems. 4+ healers. Nice burst. Shammys lack CC and they lack AoE - two things that are NICE to have when there are TONS of targets around you. Shammys also kill much slower than mages or locks and also run out of mana faster to boot. Not that you can't drink though but don't expect to go on killing sprees in the same way you can do (and I did) in AV with the mages.

Locks are in theory more viable in arenas but I don't know of anybody having HUGE success with them. When you have 1 healer in arenas - it doesn't take much to lock them down. Shammys on the other hand.... You just can't shut down THAT many shammy healers. Plus - shammys ALL have rez AND outside of arenas, can ankh. It's just an insane combo for boxing. If I were to box arenas, I would want to go shammy. I would not rule out mages or warlocks for other PvP though but don't expect to do heroics without totems or SOME kind of kiting (which shammys also have).

So it really depends on what you are looking to do. There is no compelling reason why 5 druids could not work (but cat form would be hard) or 5 rogues could not work but nothing has the synergy of shammys or mages or warlocks - which is why most people pick them. This is not to say there is NO other viable class mix - but given everything I know about WoW and knowing my objectives (PvP success as defined by more kills and less deaths) - I would go with the shammy team if you want to do PvE or arenas or mages / warlocks if you want to do more AV/WSG/AB/EoTS and not as much arena (which is almost impossible to 5 box - even Ellay 4 boxes it).

It really boils down to what is most fun for you and what your objectives are. In general though, I wold personally advise against picking 4 or 5 different classes. It's just TOO MUCH going on at once to be effective at it. You can do 2, maybe 3 things at once (1 healer, 1 tank, 3 mages or locks) but your performance at all of them is going to suffer. 4 or 5 is just too much. For highly repeatable PvE instances, you might be able to learn it - but for PvP? Forget it. You will have some success, sure, but nowhere near as much as a dedicated PvP setup. What most people don't realize is that in order to be decent at PvP, you need to be flexible and adaptable to everything people can (and will) throw at you. It isn't all pewpewpew I win.