I guess it can at least be credited to them they are listening to the subscription base. With all the complaints they've been getting about the grind, they can either add value to the leveling content or allow people a way to get through it quicker. I know WoW had a similar method of accelerating XP -- one bubble of 2x XP for every 8 hours your toon spent offline in an inn.

I'm still amazed though how the game has only been out for about a month and people are complaining how slow it is to level. Guess all the fancy graphics and wings aren't everything.

I'd be interested to know if the XP/quest (or kill or whatever) is the same in the US/EU version as the Korean.