The plight of the prot warrior and other tanks in PvP has been lamented for ages on the forums. DPSers can, of course, kill their opponents in PvP, and healers can help out their team, but the effectiveness of tanks depends entirely on a non-sentient opponent. Illidan and Archimonde apparently can't see beyond attacking the shiny person in the nice thick armor, but even the dumbest player knows not to go for the guy in plate with 15k health. Making taunt work on players is a commonly-mentioned idea, but it would take away a lot of the fun and strategy from PvP.
Prius of Blade's Edge has a new idea for helping out our protection buddies in PvP. He would like WoW to implement collision mechanics in PvP. That way, a prot warrior could "tank" by physically preventing enemy players from getting to his squishies. Warhammer Online is already implementing such a system, whenever it finally comes out (probably bundled with Duke Nukem Forever.)
There are a lot of problems with body collision in general, most of which are aptly summed up in this thread. Total body collision would allow WoW's infinite supply of jerks to block off access to banks, inns, dungeons and whatnot. PvE collision would turn raids into a group of tauren warriors standing around a boss while ranged DPS nukes it down. And, like everything, collision would add lag to the servers.
But a pure PvP collision, done only in battlegrounds or if two players are PvP-enabled or dueling, sounds like it could be a neat mechanic. Of course, I'd feel sorry for the gnomes, but maybe they could get some ankle-biting collision abilities.
Do you think PvP collision could be a viable new mechanic for WoW PVP? What problems would you forsee?