I'm in the same position as you, although I've been more willing to let figures go as of late.
I bought a lot of movie figures and ROTF toys because I was -- and still am -- impressed by the engineering. Now, however, my interest in the figures has cooled. Despite the impressive engineering, they are an aesthetic mess and I have no connection to the characters. Even worse, the movie actually soured me on the figures. I'd hate to give up my HA Mudflap and Skids because they're great toys, but they're ugly looking characters that I associate with a terrible movie.
So, I'm slowly picking through my ROTF toys and parting with them. I find that I take it slow, it becomes easier and easier to sell or trade them off with each figure I get rid of.
Anyone need ROTF Constructicons? (yellow Rampage and voyager Mix Master, Long Haul, and Demolisher). Hit me up.