It's very dependent on your server and time of day. Gorfang and Iron Rock are both the most active in the early tiers. Badlands and Volkmar are dead at those tiers, but have the highest amount of action at T4. Dark Crag and Phoenix Throne, the two servers with special rulesets are just dead at every tier.

If you're willing to coordinate on the forums, or use the new advice channel though I'm sure you could find high levels that would help you out through the apprentice system. Anyway more than most games, WAR is kind of what you make of it. I do still think the route from the middle of T2 to T4 should be accelerated though. I love T1. But I have to say I really enjoy T4 once my characters hit 40 (they feel useless below that though), I just can't stand the slog through T3 and early T4.

As to population balance, it swings back and forth. Servers were order dominated for months on end, then last week they came out with the 1.3.2 patch which reversed the balance when destro classes were ungimped finally. I think things are actually pretty balanced where it matters (scs, because honestly who wants to do the city sieges anyway), but the underdog system could really smooth out the edges. I enjoy the game for the easy access to scs at T4, but it's still not a game I'd recommend to most MMO gamers. Especially those looking for a lifestyle MMO.