I think it won't be a big problem once all Kingdom Quests are out. There is KQ's for every level, and most levels even got 2 to choose from at some levels.
Here is a list of all the KQ's from the Korean site.
http://www.fiestaonline.co.kr/system/kquest.asp
(Open in IE, doesn't seem to work properly in Firefox)
As you can see, many KQ's, so I don't think leveling will be a big problem once they out.
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