Hello everyone;
As far as I know the Adrenaline skill is ubiquitous in every build ever, and basically everyone buys into scoundrel just for this. Its just too good to pass.
I don't get it on every character ever. In fact I almost never get it unless I'm planning on making some variation of Rogue. I also don't make every character an Elf because of Flesh Sacrifice even though that's popular too.
It's a choice, not a requirement.
So throw in my humble 2 cents: Turn Adrenaline into a Talent. Something along the lines of "get 2 extra AP for the first turn of the fight.", therefore removing the scoundrel pre-req while still keeping it balanced.
Even if your Talent ditches the downside of "Lose 2 AP next turn", I still would prefer the skill, because I don't usually have a need for 2 extra AP at the start of combat, when enemies are at peak condition. I do usually need it later on at a point where I just don't have quite enough to pull off what I need to do.