They probably wanted to avoid the problem of the first game where it was too easy to overlevel, so they went the opposite direction. I prefer staying underleveved compared to overleveled, but not everyone will.
Maybe put more exp than you need laying around and have a steep penalty for exp gained once you hit a threshold level?
That's a nice simple idea. Doesn't need to be too much more easy experience, but reducing XP for defeating underleveled enemies could make sure that doesn't make it too easy to overlevel.
