A more dense population is not a bad thing...
In my experience, there is a point where, a community can be very healthy, at a population range. I'll be honest, if a community had a lot of trolls, i'd rather it be from a huge population, rather than a tiny one. But I feel that, there is a sweet spot, where the number of trolls ends up rather small, but you still have a lot of players and a very diverse player base. Then there is the opposite end of the huge population with low intelligence apparent due to lots of trolls, the ultra tiny population on a community. It ends up just as stupid.
Trolls in such a small population can be far more vocal, and heard more easily. Player diversity sinks severely with such small populations, it kind of sucks. You end up with only a few friends, but in the end, the trolls are as loud in a tiny community as they are in a large community. Players end up more divided, and extremely insecure, over the state of the community, simply due to it's small size. They get very vocal about changes, very agitated at new ideas, and more closed minded, due to the size of the community just not being big enough to foster a variety of ideas. It ends up stagnating fast.
That was, well, my experience with the unreal community, somewhat, and even more-so with the CO community. The CO community is so small, they are insecure at all times about the survival of their game and surprisingly complacent about it. They know it'll collapse and is, but go into fast denial about it when you bring it up. Any ideas posted get shot down even if it's a good idea, out of fear of the change driving the few they have left. I honestly feel, the CoX community is more alive, than CO's community ever could be, as we were diverse enough and yet, so united among each other and so with our game, compared to, well, the group that could probably fit in a small building.