Aye, I do enjoy the teamwork and group aspect of instanced PvP, but there's no rule stating the same thing can't be applied to world PvP. It just so happens that MMORPG creators just aren't that creative when it comes to bringing enemies together (to fight!).
You also have the issue of ganking. Ganking will always exist despite all the punishments the developers throw at the aggressor. So rather than punish them, just make it so a lower level can actually put up a fight. World PvP thrives, and the idea of ganking dies off.
Hopefully they don't put too big of a focus on instances; I'd rather it be a 50-50 split, or favoring world PvP. In WoW, 90% of my instanced PvP games were in Warsong Gulch, so I personally don't see any reason to have more than one or two battlegrounds, while letting World PvP be the variety.
