Unlike some other games, World of Warcraft was built on the foundations of discord and rivalry between the two factions. Namely the Alliance and the Horde. The burning hatred of the one for another might be artificial, and only there to spur the players into greater depths of entanglement inside the story of Warcraft. Yet, over the years the conflict between the Alliance and the Horde changed.
I understand the PvE players to play only on PvE servers. If I could start anew, this would probably be my decision as well. PvP servers, at least as I see them, were never intended to be a place for ganking and griefing. The purpose of PvP servers was world PvP. Even if these days, it is much more a rarity than a commodity.
I play on PvP server, and maybe this will change after our realm is one day merged with other realms. But for now, even on Timeless Isle players of Daggerspine do not kill each other, even if we belong to opposite sides. Even if the Isle is small, and has a great potential for griefing. I know when I see an Alliance player fighting with three tigers, yak and a snake he pulled by accident, I first think, if this is the ideal opportunity to help him die.
Maybe others are of more noble nature, but at the end I leave him be. Not because I could not kill him, or he could kill me, but because it takes out of my time. It disrupts my plans. If I kill him, but still stay and farm there, it means I will give him a chance for revenge. Only a mad man spits from where he eats.
What is more, with the turn of more and more attention to the battlegrounds, world PvP lost its charm. We insta-queue these days for all and everything. Maybe I am getting old and grumpy when I say we have it easy these days. The charm of world PvP should have never been about ganking some low level rogue just because you can. That is a cheap shot.
Maybe it would help if World PvP was only possible between the players of their own range. This could solve some problems, and effectively nullify gankings, but to what end. To try and revitalise world PvP that is gone for years now.
I know I was cursing the thrice damned Alliance Paladin for attacking me while doing my dailies in Eternal Valley. I did not even try to fight back. Knowing I could not win, I tried to escape. And so multiple times. I would probably forget about him, but he was waiting on me whole week. I understand this is PvP server, and by playing on it, you are a fair game, but it was not cool.
I think right now separating PvE from PvP would be a good idea. World PvP is mostly dead these days, and even in the past, it was only really happening at the special zones designated for it like Tol Barad and Wintergrasp. There really is no point in going to the battleground to finish a quest for Wrathion, when its main focus point are PvE players. It could be as easily done in scenario.
But to separate all the skills... I think this is taking it too far. Not only considering it would take great amount of time, it would also bring the split among playerbase. It is one thing to require whole sets of gear if you want to PvP or PvE. It is entirely different thing if you want to create whole new style of playing of a certain class in PvP environment.
The problem stems out of concept of balance. And the rule is that all classes should be almost equally strong in raw damage potential. If on paper a paladin is a great defensively orientated damage dealer or healer, than a warrior rogue, and magi must also be equally strong damage dealers. This is something that is not true in general fantasy.
I would even claim that the fantasy genre in general is all about imbalance. Magi will have enormous offencive potential, but will die of one hit. Rogues damage will not be the greatest, but his damage potential through subtle ways of poison and similar devices will end up much higher than at first look.
Maybe trying to balance everything is wrong. Maybe everything should be blown out of proportion. But when I think of it, this is how the horror stories about vanilla always start. And remembering those stories, all Paladins ever did was either heal or buff. At times if not most commonly even do both at the same time. So maybe, that is not so good of suggestion after all.