I think eventually the game will have more content in the middle and then XP will be slowed to make room for people to do that content - so instead of 80 hours of casual play it might take 120 hours. I think the End-game will have a lot of raid/fleet action missions to keep people busy, with maybe a bi-weekly multi-part Episode. Eventaully a Romulan Faction will be added to the game as well.
I'd like to see the Gamma and Delta Quadrants. Raids that consisted of more then 5 players. Fleet Events for your "Fleet". New playable races (Romulans, Cardassians, Jem'Hadar, Hirogen, and Borg). I'd pay to have more character slots if I could play all those races. There is so much they could do to this game besides "increasing level cap"
EDIT: I'd like to see the Alpha Quadrant too. Most of the content we have no is Beta Quadrant stuff.