What drives me in the game, both to play and to spend money, is raiding and instances. What drives you is something different. We all deserve to have content in the game that we enjoy. I don't think any one group deserves that more than any other.
I'd say the content that drives the story forward (read: Open World PvE) should always get more attention than the things you do after you complete the current story (read: PvP and Raids). My personal opinion though. I certainly don't think all groups should be treated equally in terms of content release.
I would guess that the story and PvE is the driving force behind many, if not most, players. So I think those should be catered to first and foremost.