Amount of xp doesnt play that big of a role anyway.
This game is specifically made to provide players with many different skills and spells - that are specifically made to synargize and combine with each other.
The players skill and imagination on how to use and combine all those features is much more important in combat then just xp or levels themselves.
And no, there is no possibility to outlevel stuff, because the devs know the exact amounts of xp in any area. And therefore can adjust the hardness as they want.
