I think there is plenty of evidence the coaching is bad. For example, the standings and the lack of NHL ready talent.
Look at Groulx in Syracuse. Great coaching pedigree. Maximizing 3rd rounders and undrafted players. Tampa actually has not drafted particularly well in the 1st rounf. They live in rounds 2-4, and then they let their AHL staff do work. Also I don't want to hear about wasting drafr picks when you see what Groulx does with undrafted players.
Look at Scott Gordon in Philly. Great program with the Phantoms, gets the big job and the Flyers are surging. And that is another team that invested in their AHL squad.
Carolina paid to keep Vellucci in Charlotte, and he will get head coaching interviews this offseason he has done a tremendous job with the Checkers.
Who is calling McCambridge for NHL job? Where is Gernander? The AHL has been an after thought for the Rangers. McCambridge is neither Quinn's guy, nor has he developed anyone. Why should they keep him? AHL is to funnel NHL ready players to the big club. You either do that by having a developmental guy, or by having someone picked by the coaching staff to implement a play style. The Rangers have neither.