Depends on what your metric is. Large communities can be very useful for video games, because the matchmaking pool becomes larger, which means faster and more skill-accurate matches.

I play Starcraft 2, and while the pool for players in 1v1 and 2v2 is still fine, 4v4 has few enough players to where it can be a pain to match up with another team. Just takes a really long time, and you sometimes get repeats even if they're much better or worse than you, etc.