He deserves to be gone, he's not a great coach, but not everything he did was bad.
He got the players to show up and give an honest effort more than I've seen from them in many years. Whether in spite of him or because of him, the young guys who should be here long term (Ristolainen, Girgs, Foligno, Ennis, Larsson, even Zadorov sometimes) showed steady developmental improvement.
I suspect it's more in spite of him. Between natural stages of development/ages and the slew of extra ice time available, the guys you named were simply bound to at least appear as if they took a step forward. Personally I don't think Foligno or Ennis did (taking into account production versus extra opportunity this season, there's just not any significant diff), while Riso, Girgs, Zads and Larsson were each going to appear to have progressed simply by stepping up to the NHL.
Come to think of it, I cannot name one guy who was magically reclaimed during Nolan's tenure unless it's possibly Myers? Conversely, I can think of a few career grinders who he "got the most out of" merely by playing them so far up by the depth chart that they got the minutes (Flynn, Mitchell), and at least three vet forwards who stepped back under Nolan's coaching/strategies, etc. (Moulson, Hodgson, Stafford) - more if you're looking at points per 60 for one example of a measurement, including Ennis, Flynn, Foligno, etc.
Lots of factors at play, sure, but without being able to name one guy who hands-down genuinely improved during Nolan's tenure and yet being able to name several who had worse showings, I'm just not seeing truth in the myth that Nolan "got the most out of a pathetic roster".