I don't think Blade&Soul is coming to NA, but I've been playing it for a while - http://playbns.com/
In terms of hype up-coming MMO's take a look at Skyforge
You can't prevent mods, unless it uses the same system L4D does but even then you can use sourcemod to change the gameplay.
Guess what else has matchmaking.... Team Fortress 2.
Guess what TF2 has... dedicated servers.