What you're asking for is a straight Death Match type of Battleground. I'm not sure it would be compelling as you think. I'm a big fan of DM as well, at least in FPS', but for an MMO like World of Warcraft, I question how enjoyable it would be in the long run for people. I think for players who feel very comfortable with their abilities, straight head on PvP like that would be fun for them, but for others, I'm not sure it would have the same appeal.
That said, I'm not killing the discussion. I'm just interested in how you feel this would work or appeal to a wide enough audience for it to be worth creating.