Similar to thug perk and how it works with rage now it would be great to make some feats more useful.
Stealthy feat for example - Maybe make it grant extra bonuses to pure rogues/wizards/sorcs/rangers?
Resist poison/disease - maybe rest removes all poisons/diseases? and maybe extra saves vs poison/disease if you remain pure class
Bloodied - no idea
Bull headed - fine as is
etc add your own