Add me to the long list of agreeing this is what to do.
1) Most people over value themselves to a fault at work. Very, very rare is there an irreplaceable employee at an established company. (Once you get into management and ownership you start seeing it more often, but even then, it is pretty rare.) So there is a very, very real possibility they don't give two fucks that you are leaving.
2) You said you've complained before. Given the childish need to shit on them as you walk out the door,(I did it in my mid 20's myself, so I'm not judging as much as pointing out the truth,) it isn't a far stretch to say your complaining about opportunity was annoying as shit, they are happy you're leaving.
3) In professional services a hungry employee that asks for more responsibility is only denied that opportunity when they suck. I understand the traditional corporate world is different. If you were denied the opportunity because you sucked, they are happy you're leaving and will laugh at you as you walk out the door all angry.
4) Like I've said, I've done what you want to do. You know what it got me? Nothing. Not a single fucking thing. My next job was 3000x better, and the old place is still going and haven't changed a thing. It was a pointless waste of time and effort to even care. Just... Move on, and put that drive to shit on them into something else. Sure you may get a couple good zingers in and hurt some feelings... But you'd be better off fucking a hot co-worker or two and bouncing, pretending you loved the place.