This is the worst idea I think i've seen proposed on the boards!!!
You're litterally saying pvp should be on all servers. Novice idea and maybe even a little interesting seeing how duel total blows. But your saying that you can turn pvp on and off?! Are you even on a pvp server? I don't know about T8 but from what I hear you can be caring around a few platinum from quest alone. Allow pvp instances on server is the ultimate easy mode. Its worst then regular dungeon instances and cities to the max!
What pvp needs are more zones like Sinking Sands and Enchanted Lands. Theres a reason those zones are so heavy on pvp its because they're desirable. Less content in a zone = better pvp zone. Take timerous deep...that zone freaking sucks! I wish there was a way or an incentive to designate old world zones as pvp hot spots. It would be great to see total war zones in nektulous forest, island of mara, steamfont mountains ect. Now when you pvp all you have to do is stand in enchanted lands or sinkin sands (kylong plains for higher tiers i believe) until you've killed someone enough times a x3 raid comes out of no where.
Allowing to turn pvp off is the worst possible idea.