To actually answer the question, I believe his "tragic flaw" is his misuse of our roster.Obviously, it isn't the only problem Carlyle has when it comes to coaching the Leafs, but it is, without a doubt, his most tragic flaw. Here are a couple of examples:
1. His offensive game plan does not utilize the skillsets of the forwards on our team. Carlyle enforces a dump and chase/cycle policy. You see, in order for this tactic to be successful a team needs forwards that will actually chase a puck and WIN battles down low. We have one forward that can do that - David Clarkson (another topic entirely with that one). We have a lot of soft forwards with skills that are suited more for a run and gun-type offense.
2. THE FOURTH LINE. What the hell is he doing? First, he unfortunately places Peter Holland at center on the fourth line between Colton Orr and Frazer McLaren. WHAT?! That is a massive waste of talent right there and entirely detrimental to the development of Holland (who is very talented). It would essentially have been the same if he put Holland out as the only member of that line. So, Nonis sends Holland down after this happens and calls up Carter Ashton...who Carlyle then places at center on the fourth line...between Colton FREAKING Orr and Frazer "USELESS" McLaren. Keep in mind that Ashton said himself that the last time he played center was back when he was in JUNIOR!!
Let's get real guys, we need to have a fourth line that can play more than five minutes a night. Having a reliable fourth line that can play and bring energy to a team lightens the load that much more on the other three lines. The other three lines get more rest, which would allow them to be more explosive when they get their regular shifts.
There are way more issues to talk about but I don't have time to talk about them right now.