Same here - I've used Quinn a grand total of twice and I'm 47. I keep Vette geared, and occasionally use Broonmark. I've never been anything other than Carnage specced, and I have never "needed" Quinn. It's just a different playstyle. Without a healer, I tend to be a little more focused on burning down everything as fast as I can - interrupting everything as soon as I can, and using all my defensive cooldowns at opportune times. Using force cammo to bounce aggro is a great tool that's often overlooked.
I know in games past, when I've had a pocket healer, I personally have tended to get lazy with the button spam, not paying as much attention to "rotations" (for lack of a better word) and just spamming things down to dead. Can make alot of fights more difficult then they should be.