I wonder what Dubas has to say about that kind of thing:
"We don't want our players going up to the Leafs before they're ready, and we don't want them shuttling up and down. We want players to be called up to the Leafs when they're young and on the first two years of their entry-level contracts ONLY (his emphasis) when they prove that they can be a Leaf, all the time. We don't want players going up and then coming down. We saw last year with Percy and Carrick, they go up, and they come back down, and it really rattles the players' confidence. To make the team and get recalled, it gets your psyche out of order a little bit. And I think that's on us, it's not on the players. We have to be the ones making sure we're doing what's right by the players."
It's interesting how you simultaneously accuse Dubas of being horrible at development, for doing things that everybody else does and have been historically perfectly normal in the development of top-4 defensemen, but at the same time, hold a cherry-picked, incomplete portion of one answer of his from one interview (largely about the Orlando Solar Bears) from almost 6 years ago before he was GM, as the one and only gospel on development.
I'm not sure how you twisted his statement that basically amounts to the importance of patience, into a narrative about developmental incompetence because Sandin wasn't handed a spot on a competitive team out of camp. You create insanely specific and arbitrary rules, and accuse others of not understanding development, when the first thing anybody should know about development is that there is no one perfect way for all players in all situations, especially during a global pandemic that has delayed or cancelled countless leagues.
For the record, this was the question that was asked...
Don: The organization has talked a change in philosophy toward prospects, and not pushing them, letting them develop in their own time and then moving them up, talk about that and how that might affect the number of players that might be here in Orlando from the Toronto organization. I get the sense that you're looking to have more players than were here last year, down.
And if you'd read it, you'd know it's mainly in regards to the Orlando organization's inclusion in the development process. Actually, it's pretty hilarious because the main takeaways are about not rushing your prospects before they're ready, and not getting hung up on the league somebody is in or giving in to pressure to play somebody somewhere - instead just focusing on what's best for their development. In the previous question, he discusses how moving down a league and being patient has helped some of their players.
In the part you highlighted, he references Carrick and Percy, but that's because, unlike Sandin, they weren't remotely close to ready to be in the NHL and hadn't actually proven themselves worthy of a shot through their play in the AHL, but were pushed to the NHL anyway. This is not the same situation as Sandin. Sandin was not pinballed, and Sandin
had proven himself to be worthy of a shot in the NHL. He was not ready at the beginning of the year, and was sent down. He then went on to play really well in the AHL, and won top defenseman at the WJC. He had earned another shot, and there was an opening caused by extensive injuries to the Leaf's defense, including a player who was most similar in style, position, and role.
Was Sandin good enough to play in that situation and get some experience? Yes, he earned his shot, and showed some good signs.
Was Sandin good enough to warrant handing him a spot out of camp, and limiting depth signings on a competitive team, especially when they needed so much defensive depth the year prior? No.
That doesn't mean that Sandin is bad, or failing, or being developed poorly. He's still really young, and we have great depth this year, with no injuries thus far. By the logic you are using, Sandin would be developing just fine if he didn't play in the NHL last year, which doesn't make sense to start with, but then if Toronto had all those injuries and didn't play Sandiin after great AHL play and WJC top defensemen, you'd be complaining about his development just the same. No matter what Toronto did, you would have used it to claim "bad development".
The development track Sandin is on is perfectly normal, even for high-quality NHL defensemen. Your claims are baseless.