Faction points?

[The Cid]

Maybe it would be more balanced if You would limit the stats You can improve to the special abilities for each class, eg archers can only improve archery and power draw but no iron flesh, athletics, one handed skill and so on. Depending on what the class is supposed to do You could/should also set a limit for a max. skill like Wardens can improve archery by 30, Rangers by 20 and Sentinels 15, though they can improve other ones of their stats higher than compared to the other hero classes

This is a good idea.