By that point the dev crew that's working on updating WoW will also be decreasing in size, as the majority will be rolling onto making the next big thing.
That's just common sense. They will milk the most out of wow for the least amount of work. Making new server types is NOT a small amount of work. So if you are a wpvp hopeful wishing for big changes from blizzard to make wpvp have more incentive than instanced pvp...well you are in for an awfully long...LONG wait.
(this means get comfy with server factions being skewed drastically as players actively work to avoid any kind of shit that slows down character progression)