The player base has reduced a little since the release and most servers are dead as dead can be, however they are "fixing" that by merging servers to increase the population per server.
This could make the game more fun for the people that play the game, only probably wont let players that left come back to play the game.
There is simply to much competition of other newly released games.
Best way to maximize effect from this merging of servers is by giving a week or so perhapse a few days of free play time for all account.
Also for the frozen accounts, this way the players that left can check the game again and see how the population has increased and enjoy the game again.
If they dont then this merging of servers would only help the current players on empty servers, the players that are on busy servers and are in raiding guilds wouldnt really notice much difference.