Sounds like trouble
Some problems that you most likely thought of but should keep in mind if not.
Kill stealing/kill griefing. Anyone with higher damage output of AOE can just grief players trying to fight in non pvp areas getting the kill shots in and blocking players from getting xp.
PVP Border hopping. Using the Non PvP areas to escape PvP.
AFK Macro. Most likely will not happen if the dungeons are well traveled but could be done rather easily if they are not policed.
If I think of anything else I will POST it just to make sure the problems have been thought of.
EDIT: Unless you would rather me bug, exploit or private convo post it.