I'm curious to see how Benning supporters can spin this
I'm pretty neutral on the whole Benning thing. He's made better moves recently, but there's a lot of dead weight on the roster that's all on his shoulders. There might also be some pending dead weight in Roussel and Beagle, but at least this season they've been exactly what we needed in the bottom six.
As for the goalie situation, I honestly feel like they didn't think Leighton was going to be ready to play and expected him to be a stopgap at best. He showed he could play and seeing as McKenna has looked awful in the AHL they decided to go with him as third on their depth chart. This bumps Mazanec to fourth on the depth chart and he'll be down to the AHL once Demko is healthy.
As to why they didn't do all this sooner, Leighton probably took time to decide if he wanted to play again this season and then there was more time to actually report to Utica and play himself into shape. The Mazanec thing was a casualty of them playing wait and see with McKenna and getting screwed by the Flyers. I can see the logic in waiting but it's not the choice I would have made.
The same goes for how the McKenna trade was handled, I get wanting Demko up ASAP, and they likely didn't have many options for where to send Nilsson for a goalie in return but if they'd waited two weeks or made Ottawa waive McKenna before the trade nobody gets claimed and we never get into this mess at all. They could have also made the trade and waited on bringing Demko up until the Flyers and Leafs had sorted their goalie issues. Everything after McKenna getting claimed is due to Benning not having planned for McKenna getting claimed and then trying to play it cool in what would usually be a low-risk low-reward type of move. It didn't pan out, but honestly, we're not exactly far behind for having tried it.
Realistically we lost one game for having started DiPietro, it probably won't hurt his development long term and if it did he likely wasn't a prospect anyway. Beyond that, we've picked up two solid goalies for Utica and spent a 7th round pick and two contract slots to do so. The optics, in this case, are far worse than the actual results which are a slight positive for Utica and a net meh for the Canucks.