thinking about it, the delay for NA/EU could have more reasons behind than simply getting the publishing rights and doing the translations.
maybe at the moment Aeria is also waiting to see what happens in KR after the server merges, to see if it's actually worth to invest time and money in the project.
anyhow, after making an official announcement of partnership with Neowiz, i doubt they'll hold back.
right now it's all about server situation.
if they see that the merges were needed only because there were too many servers around, then there should be no huge problems in the future.
implementing new features along with new content may as well bring back some old players, while getting new ones too.
however, if their playerbase keeps going down in the next months, then the problem is not in the quantity of the servers, but rather in the quality of the game.
there's tons of features that could be added, so i really hope that they won't screw up the game.