Warhammer Online is like three games in one. And that's not a good thing, in this case, because its like three separate games that don't have much to do with one another.
Right now, you have Scenarios, which are a blast. You launch into a Scenario (instanced RVR battleground) from anywhere in the world; this means if you want to play Scenarios, the world itself is largely irrelevant since its a just an overly decorated lobby. And that, unfortunately, is how most people play the game, since the rewards for PQs and Open World RvR don't match.
The other game in Warhammer is the PVE game. And while PQs offer a nice incremental improvement over it, they are only sporadically populated in the higher tiers, and most of the time, I see people only at the PQ nearest the camp for that Chapter. The biggest problem with PVE right now is that its actually more rewarding to grind the soloable first part of a PQ by yourself... which is counterintuitive and undermines the community-building nature that PQs and Open Groups were meant to encourage.
And, last but not least, there's the Open World RvR. In theory. I've seen this only a few times, and only when my guild mustered up people to take on a Keep. But while its great fun to storm a Keep, ultimately its not very rewarding. In the time it takes to run back and get one-shotted again (I'm playing a Bright Wizard, so that doesn't take long), I could play a Scenario and get better XP and loot...
Any one of these sub-games would be great in its own right. A PQ-based version of WoW would be amazing. A game solely focussed on Open World RvR would be fun. But as long as the rewards remain out of balance between them, the whole game suffers.
Mythic has been very responsive so far, improving XP for PVE and RvR. I'm still planning on continuing to play WAR; I just subscribed for three more months (on top of the two subscriptions I have with EQ2!), so I'm still convinced in the future of this game. But to keep that fee past January, we will need to see more improvements besides simple XP boosts.
There also need to be fixes to itemization so that RvR rewards justify the time and effort invested.
We also need better travel options. Scenarios aren't just popular because they give better XP; they are also popular because you can get into the action very quickly. There are too many zones where (even on horseback) I have to run around forever to complete quests. Better PVE travel options also means more people can get to the Warcamps faster for RvR.
I would also like to see dynamic mechanisms created as a way to TIE the separate games together into a more cohesive whole... so, for example, if lots of players are in PVE dungeons or Scenarios, maybe that gives the RvR players some sort of bonus (because our warriors are stalwart enough to defect some of the meanest and nastiest critters to plague the lands, see). It may seem counterintuitive to reward someone OTHER than the ones doing the work here, but the idea is this: if people are doing really well in the dungeons that means they aren't in RvR, so this helps encourage people to come back out into the daylight and venture onto the real battlefields; it also gives a little boost to the people who are already on the battlefield to make up for the fact that all their friends are underground. The other advantage is that the game feels less like three separate games and more like one interrelated whole.