Thanks for starting this discussion.
IIRC -- his deal ends up getting friendlier by two million a year less from here on out until it expires, but regardless I think he should be a candidate for re-structure for the two years over 10 million that still remaine. I can't imagine he gets dealt in a trade with how high his salary is. That is just my personal opinion on the matter. There is a lot to like about what he can do in the pass rushing department, but have always felt his performance against the run was average. However, he seemed to make some plays in that regard this year and did a great job forcing fumbles (6).
There are a lot of good edge rushers in this draft who I would like to have added to our dynamic. I don't think that Robert Ayers is a replacement for Dumervil, but someone we should consider retaining for depth as the future goes on. Jack Del Rio absolutely raved about Ayers when he was coaching at Mobile, so perhaps he will get an opportunity to shine in 2013.
FWIW, I think we clearly need to add another DL with some pass rushing talent to who we have right now. We had some great sack numbers this year, but we could put on some more firepower there. We didn't get much penetration against the Ravens in our Divisional Round loss.
In short. Dumervil should be a candidate for re-structure to save a couple million now and 2014. Don't think we have anyone who could realistically replace his production on top as of right now. Plus his middle name is Kool. Koolbeans.