So for a party game you expect that only one class can achieve everything

. You cant do that! Thats not how party-based-games work.
Its totally your mistake. Create a new party and put some points in Water than you can heal yourself. And Lone Wolf is not for beginners.
Go try playing DnD with only one class the whole party

.
I am not a beginner. I played hours of Neverwinter nights and know exactly how to spec.
This game is just bad. I have managed to beat Evelyn solo by stealth, it was easy. Why won't the game let me beat everything else? Because it is not free at all, it's an "On-Rails" adventure game.
You can't multiclass properly in this. I basically aimed for an archer who could solo the game with stealth, but virtually every enemy heals in this.
I took out all of Braccus's enemies, and everytime you hit Braccus guess what, he heals. Do you think these are good enemy designs?
I have played a lot of RPGs and this is not one. It has everything that makes an RPG missing.
1) No NPC smiths that can craft weapons for the player.
2) No freedom. On-rails everytime you start.
3) No dual weilding.
4) No balanced multi-class.
5) No classic stat bonuses or penalties.
6) Cheating AI.