I have never found a MMO more tied to the number of people playing and the amount of fun you have in the game, than Warhammer. Lately I have been finding my server to be a bit under populated, which translates into pitifull RvR, long waits in Scenarios, and absolutely no help in Public Quests. The fun quickly dissolves in Warhammer when populations are low, or worse lopsided.
Pure soloing in the game is an absolute drek of boredom, killing one mob after the next the creatures spawn so quickly that you rarely need to move. The creatures themselves, as long as they are not Champions, can be mowed threw like cutting grass. Xp is quick and furious in the game, but lacks any real tangible feeling of success.
Groups are hard to come by unless doing PvP or RvR, and when the servers are low it can be a long wait. I often find it hard, even jumping to different maps, to find groups of players.
The game seems to rock from 8 PM to Midnight, which for the most part is the majority of my playing time — but the mornings I get up early or on vacations — Warhammer is not the game to play.