You don't have slow progression in this game due to ganking. You have slower progression in the game if you are on the more populated faction. PvE questing for levels is optional.
- You gain EXP at a very nice rate by doing scenarios (BGs). I got 1/3rd of a level with one victory when I was around level 3-4. There are also quests to turn in for each scenario to speed this up even more.
- Your ques for the scenarios pop more often if you are on the lower populated faction.
I'm leveling faster by just doing scenarios and a little bit of PvE questing because I'm Order than if I was doing PvE questing with some scenarios as Destruction.
This isn't like WoW which has no upside to being on a RvR server. The key changes are that you are always flagged and that you can go into another tier lower than you can on a core server without turning into a chicken. Basically, the battles are tougher and more often.