I dont see why RP servers couldnt be in the normal system of WvWvW rankings. Even if they are not as good at pvp, they would be eventually ranked accordingly by the nature of the system itself. I dont see why RPers should be worse at pvp though. Mostly they attract more mature players (big assumption here of course, but its my experience) who are more than competent in pvp.
I don't see RP servers happening because of WvWvW.
Would they match up RP servers against a regular server? Probably not. Then they'd have to create enough RP servers so that you can regularly switch up what other RP servers you go against in WvW in order to create a fair balance. Unless the RP scene was big enough it just couldn't happen.
That's my thoughts on it at least...
WoW has battlegroups of mixed realms. Why not GW2?
Battlegroups aren't as important or as large. They don't effect the server at all.
Then there's the whole, you can visit any server you want at any time thing. I see a bunch of players that think RP is a joke flocking to these servers just to mock the RPers. You know how some people are...I don't see them disallowing people to visit a RP server since everything ArenaNet is about is community, and that just splits up the communities. They want people to be able to play with friends, where ever they are.
There could always be an un-official RP server, and you'd be able to go there and visit it at anytime too.
Anything now is just speculation though. Maybe it could happen, they're smart enough to be able to solve any problem thrown at them.
Sure I guess people could come and mock us, but its not going to be a huge problem especially if people were banned for it.
And you say its about community, but surely the RP community will be split up if there is no official RP servers. It seems to me that it would help the server community, not hinder it if lots of people are there for the same reason.