It wouldn't even be the first time. Are we forgetting he took a 95 point Ducks and turned them into a 76 point Ducks the following year? I guess those 10 wins just slipped away from him somehow.
A couple points on this general topic (Babcock and playoffs):
1) That 2002-03 Anaheim roster was not exactly replete with awesomeness. It's all relative to what the rest of the league was like too, but those ducks were Kariya, Sykora, and system. It's a little harder now to defense your way to the Cup because pretty much everyone focuses on defense more now than they did 10-15 years ago, so facing a stifling defensive system isn't the curveball in the playoffs it used to be... but still.
2) That offseason was the one where Kariya left and Fedorov arrived, along with a bunch of other roster changes, and along with a decent amount of blue line injuries. That roster got a lot less defensive minded (33 year old Feds proving he was The Man(tm), Prospal, Oates declining, Havelid stepping back) and didn't really have more offensive firepower to make up for it. Narrow margin.
All that said, do I think Babcock is going to get the Leafs into the playoffs next year? Probably not. I think year 1 is mostly going to be him kicking the bleep out of guys on that roster to see who can stick and who has to go. I don't think the Leafs are actually a 68 point team though, so the 'he's going to account for 15 wins?!?!' thing is a bit much. Toronto was in the playoffs in the short 2013 and they were 10 points out in '14. In '15 they just did the tankapalooza because everyone there knew the organization was a zombie, 68 points isn't representative of that roster.
It could happen, though. I'd say there's maybe a 30% chance of it as of today, but it's not like I look at the East and go 'oh yeah, there are 8 lock teams I'd take ahead of Toronto.' Heck, first year into a transition staff with a transition roster is anybody going to puff the chest and say
Detroit is a lock for the playoffs next year? Not me.
And oh man, Toronto in and Detroit out? Oof. There'd be some soul-searching.