Harper seems someone thought in a hurry, mixed stuff from half a dozen different trees, added melee power "'cause now we have to have melee power", and thought "There! It's done".
I can pin almost every enhancement to a class, so I guess Harper is the Half-Elf of Prestiges.
Minus the anime eyes.
Why do we need Harper tree? We have 80 AP to spend, which are usually already thin (I always multiclass, but even for pures, 1 race and 2 class trees is sometimes hard - which is understandable).
Suggestion: add 1 AP per epic level. That will be +10 when level caps at 30. Seems reasonable, I think.
Carry on.