Nats went after Lynn at $10 million per year rather than Morton at $15 million per year. The Lynn signing would have been a net break even with Roark leaving. Signing Morton would have been a 5 million net salary increase. Or in other words after signing Corbin the Nats are not going all in but rather trying to find some bargains. I think this generally fits the pattern that they will pay their top guys but want discounts on the rest of the roster. Roark would have been a dependable number four or five. But losing the salary was obviously the priority.
My comment about this being a better contract than the Lynn contract had nothing to do with "which would have been better for the Nats had they been involved?" It had more to do with my low regard for Lance Lynn and respect for Charlie Morton, and was not Nats specific. Also, given the budgets and competitive position, it's interesting that a team with a very low budget went for Morton at the higher AAV than Lynn.
Since you put it in Nats context, I would have wanted them to be in on Morton on this kind of contract regardless of the Roark deal. More or less, after Corbin, Keuchel, and Happ, Morton may have been the best FA pitcher for the short term, and he's not making anywhere near as much. Lynn and Miley are a completely different class and should be paid less.