Johnston's bench management sometimes doesn't put this team in a favourable position. Systems wise, though, he is helping their chances of winning games. Of course, you will have games where they put up a stinker. But that is more on the players IMO.
Another thing is the team - as it is heading into the playoffs - just doesn't have the personnel to compliment it, especially on defense. Having Maatta, Ehrhoff, and Letang back there would help. Plus, adding Dupuis wouldn't hurt. People can scoff at this thought, but injuries and low sh% are making his system all for naught.
As for the other coaches you mentioned. Babcock for sure. Tippett and Hitchcock too. But Deboer? He's no better than Bylsma when it comes to having a system and making adjustments. The Devils made this Pens team look exciting with how Deboer had them playing near the end.
Near the end, everyone but Jagr quit on Deboer.
I think you might be mixing up grievances. Deboer makes adjustments, alright. I mean, that's what got him to the dance--and the finals--not a charming personality and a great roster. He's renowned as a somewhat brilliant tactician. An innovator.
What Devils fans didn't like about him is that his adjustments didn't involve very much youth (not that the Devils even have any youth to begin with).
I agree that Johnston is very academic in his approach. But he also doesn't seem that creative at this point...
...
Innovation and effective adaptation seems to be asking a lot, but there it is.
Johnston's in-game adaptation is mostly fine, considering what he's got.
But creativity or innovation is not there, no. He will never, ever, think of something someone else hasn't already thought of, preferring to copy and play things by the book.
That's a weakness, sure, but there aren't very many coaches that have what you're asking for and, to my knowledge, we didn't interview one of them last summer.