I know that rage was usable on enemies and that they used it as well, recently the change to remove that made me think that a rebalancing of the skill (cost, cooldown, its values etc) would have been more preferable since I really like the idea of a melee centric caster specializing on magic damage.
I don't have any problem with elves getting "free" skills as long as their power is tied to their respective schools, adrenaline is a powerful "support" though and doesn't really suffer from that.
Walk in Shadows / Chameleon as someone mentioned is a headscratcher and ties into my observation that the powerlevel of source skills atm is all over the place....I am sure larian will further work on that and we really don't know atm how common/easy or hard it will be in the further acts or patches to obtain source points.
Skin Graft for me stands out as the single most OP skill in the game, especially when paired with adrenaline atm. It also helps with point investments at level up since if you don't wanna autoattack now and then you would have to invest into memory, skin graft devalues memory as a desirable stat and frees up those points to invest into damage.
I really don't have a clear vision for this and don't envy larian, I posted here purely out of selfish reasons since rage+magic melee is a beautiful thing

One possible change that could be made would be to either make rage and aura that affects everyone in a certain radius or make it an AOE skill centered around you so you still need to get into melee range but get affected by the debuff part of it as well.