It's because Teva has a larger population of players which range from the actual newbies, beggars, bots, high-level people, assholes etc. Basically, the average population of a MMORPG.
Its funny that you should mention that. When I played the other day on Teva I noticed a lot less lag, a lot less people in Roumen, and a lot less kill stealing going on. Whats the deal with that? That right there makes me want to move to Teva immediately.