In RaidFight history, it is a fact that every time a big server opened (like rpg did with their x5) some people left to go there. When that server closed after a couple of months the players return, brining with them more players. Till now, rpg has closed many servers and helped us a lot to grow. So I am very optimistic.
Now, another RaidFight fact is that, every time a (pretty big) server closed, most of it's players came to RaidFight: Linezeus, mooage, elixir, pilgrims, rpg-club, l2retail made us from a small server with not more than 100 online into a server with 4000 online.
There is no big or small when we talk about community, because if there was, RaidFight would have closed years ago, like the rest.