I haven't played Bastion, so I can't really speak to how that worked.
Quentin might have gotten off a little too easily — it might have helped that scene to see Hawke walk over and stamp on his neck a few times —*but I don't feel removed from the tragedy because I couldn't stop it.
To take an example from Bioshock:
SpoilerI find the scene where you beat Andrew Ryan to death no less powerful because I'm not swinging the golf club.