This is where I'm not aligned in the thinking with the vast majority that want McCoy. It isn't about being cap savvy; it's about ensuring you have the necessary cap space to retain your core, which should be priority #1. And maintaining the ability to maximize your ability to build a strong team in future years as you are now - sustained success. Any move that negatively impacts that should not go through. I'm not saying acquiring McCoy does that, but as of right now it's in the range of potential outcomes.
Does McCoy make the 2019 Browns better? Almost certainly. But he also may indirectly make the 2020 and beyond Browns worse. What are his priorities and actual market? Then how does acquiring him potentially impact future season's? We'll know the answer to question #1 shortly after whatever contract he signs, but we won't know the answer to question #2 for some time. Optics will likely dictate that question meaningless because most won't remember, but I think sound fiscal policy/planning is more important.
There's a price that makes sense for a great rotational veteran DT, but beyond the indirect impacts it has on the rest of the roster in future years he first must be okay with such a role and second his cost should be substantially lower than the DT you signed 2 months ago. This could be a great get, but there are a lot of variables that need filled in for this to make sense.