The best way to go would be Talent Trees:

1) Make them respecable
2) Make respecs free
3) Allow us to respect anywhere not just at an inn or NPC
4) Let us save "loadouts"

This way you can set your loadout for each type of content for fun solo play or according to party needs/demands

I like the way that APRGs and other MMOs (like WoW, SWTOR, ESO) go about this - in that there is a healthy mix of a variety of passives which tweak skills in certain ways. I think games like SWTOR actually got talents right when they pruned their whole talent system last year.