I'm really not a fan of breaking up what has worked. If my experience watching NFL games tells me anything it's that you want overwhelming talent vs. just enough. I like Wilkerson and as well as Richardson has played in his absence, I wouldn't want to have to rely on him without Wilkerson on the roster. And when you're somewhere like $40 mill under the cap, why wouldn't you tie up a chunk of it on, arguably, your best player(s)? Especially when the majority of it is likely to be money that can be restructured or withdrawn in a couple of years.
I don't think you need an "elite pass rusher" when you have three very good pass rushers. My desire for a great OLB has more to do with having an elite defender for the second level of the defense. Sure, rushing the passer is part of that. But so is the general disruption that an elite OLB can have on an offense, whether that offense is running or passing; being able to cover someone man-on-man. Being able to blow up a play so hard that it results in a turnover. This Jets defense, even in its heyday, didn't really have that capability.