Two things...
-No, the engine is fine, it's the content of the game, not the engine that is the problem. Crystal Tools can obviously do the job- it's just been poorly applied (see XIII)
-Blade and Soul is a kMMO that has been in the works for YEARS to beat out all of the cheaper kMMOs and replace Conquer as the "kung-fu MMO". It could be amazing, it could be another crappy Unreal game (or Blizzreal knock-off)