It works for reducing experience, but how about adding in a bit of an experience boost when learning skills far below your level. It doesn't have to be as extreme as the falloff of learning above your skill level, but it's a nice boost to bring something up that you haven't had time to level before or just now decided you want. Here's what I had in mind:
1 level below - 0% boost
2 - 0% boost
3 - 2% boost
4 - 5% boost
5 - 10% boost
6 - 17% boost
7 - 25% boost
It doesn't even have to be that much or that close to your level, but a little something would be nice
