Recently, I was playing with my character, who is a marksman. I was using the bow and noticed that when I used it and charged the shots to the maximum, my progress in the “Power Attacker” augmentation increased. This is strange, considering that the bow is incapable of using the Power Attacker. So my suggestion is to allow the bow to use this augmentation. Since it’s odd that it can level it up, but not use it.
I don’t really know if this is a bug (although it probably is), but I think it would be interesting if it were an option in the game.