Yeah it will come down to what they do with Donaldson. Trading impending free agents to add more talent to the farm (if they are out of it in July) is one thing, but Donaldson is pretty much the franchise altering player. If they move him, the team is not going to be good for a few years at least. If they keep him, then they run the risk of losing him for a bag of chips after 2018 (or whatever the compensation is for losing a FA in the new CBA....3rd round pick???). Plus, if the team ends up being mediocre or trash in 2017, will it really get any better in 2018? What they do with JD will shape everything.
I agree with your general point though. They got the team back in the playoffs in 2016 without touching any important prospect (they actually added to the farm in that time), and on paper put the team in a competitive spot for 2017 without losing any prospects either. I suspect they will go on a run soon, but whether it's enough of a run to a) be a legit threat for the playoffs, or be in a spot by July to avoid a Brian Cashman type of sell off, is the question.