A lot of servers (that I've seen) really need a merge or a mix with other servers.
I'm in a server where the top 20 on every player leaderboard tab belongs to the same guild. A guild that only approves members that have put more money into the game than my house costs and who then like to brag around on global and everywhere else possible on how fabulous they are. Needless to say that it kind of kills the point in even trying to play on that server anymore.
This guild actually ended up in the same server as me with a merge but because ever since then nothing has changed they've pretty much taken over. Because it's an older server barely any new players will join in so competing with said guild is impossible.
And to add... some servers might be kind of dead... so that's another reason I rather lose a bit of rewards in the game and have new players in the same server.