Not to sound like a homer and I don’t know much about Keefe, however, I think some of the blame goes to a very talented team that seems they can’t handle the pressure of the playoff.
As an outsider this seems like a great hire. Some leaf fans as well as their president seem unable to admit the main reason they keep losing in the playoffs is their roster construction. Every year because of their ridiculous cap distribution, they overhaul the non - core guys every season usually with lesser and cheaper players while not addressing the actual problem of their 40+ million stars doing jack shit.
Keefe, despite significant roster turnover every year that saw more and more tweeners filling spots had the leafs always finishing near the top of the league. If the devil's can get a goalie and stay healthy and the GM decides to exchange some prospects for some pieces further along they could be a top team under him .
On the flip side if Berube is stuck with that core of proven chokers with no big changes nothing will change.
They should have fired Shanny into the sun before anyone else