I wish more companies just thew on a translation and released the game. The benefits are just so huge in that you can almost always keep up with releasing the same update at the same time both in west and east. (Because you can translate text while they program)
Not to mention most people want to play the Korean game, but don't want to steal IDs and play something they can't read. So you'd be doing your fans a favor, while saving yourself some headaches.
Unfortunately it's not quite that simple. You have to worry about voice-over recordings, asset integration, linguistics testing, and making sure strings of code are localized 100% properly. Even 1 foreign character in core coding can result in the game crashing on an EN PC that does not support it. Then, all that must be tested on a higher scale (i.e. Closed Beta).
A localized version of a game is virtually a completely new client, and thus must be treated as one. The same applies to updates. Just as they are tested by internal testers for the native version, the same must be done for the localized version.
Generally a developer won't sign their game to foreign publishers if the game is not successful in the native country, this is partly why the native version of games tends to be ahead. I do not believe Aeria has any choice in this matter.