They basically need a plan to win in the next 2 years before Doughty requires a new deal, whether he stays or goes. Especially if they buy Gaborik out, and his dead cap space triples, at the same time as Doughty's contract expires, and who knows what the league's cap situation is by then.
If you're cleaning house in management, and not trading any of the core players, there's only one option, and that's going for it now. What happens in the summer of 2019, that would have to get dealt with the closer that day comes, not worried about today.
Not much in free agency on defense, but they seem ok there. A few guys out there up front, but you figure some young guys from Ontario will get the chance. Free agency is for filling in specific holes, so you want to be as efficient as possible.