sounds fun, but maybe they could put a level limit on it. Like say a group of level 35 go in...if it is to be shared then only a group of matching level range should be able to open pvp with the group? So, people level 30-40 or something, for example. But, then this may eliminate dungeon "run throughs" by ignoring extra help outside the level range. But, even then you could have multiple raid groups of same faction/level range come help and then what's to stop a raid group of similarly leveled players from opposite faction stomping them anyway lol
I still like the idea, but I self-defeated it

I guess you'd just make it open dungeon rather than instance. But, that seems like it would open the floodgates for mass griefing =\