Work ethic is often confused with working smart--it's a complicated area. What I see with this version of the Leafs is that they use up energy (work) but tend to get very frustrated when their energy doesn't get them the results they want. An example of this is Marner and Matthews trying to over-stickhandle or make high-risk, no-look passes that result in rushes the other way. The players are using energy (working) but they are not working smart. I don't think anyone on the Leafs is "lazy" or just "mails it in"--but they are convinced they can just win on talent alone and they don't want to do the dirty and uncomfortable things it takes to crunch out wins.
And this is obvious because it's exactly why Babcock was fired--because he demands his "stars" roll up their sleeves and get dirty when needed. It's how he won in Detroit--Zetterberg, Datsyuk, Kronwall and gang did all the things asked of them--the Toronto kids ultimately refused and tuned him out--they were convinced they could win "their way." They refused with Babcock and they are refusing with Keefe.
I blame Shanahan and Dubas for this--where is all the veteran leadership? Where are the players on this team who won Cups? Who are the vets on this team that the young kids could look up to and learn from? Where are the vets who can pull Marner aside and tell him to cut out of the fancy crap--but a vet that Marner will respect and listen to? There are none. They have Spezza, but he never won squat, is/was as soft as they come, and he's a weird cat personality wise--he's not a veteran leader with chops and war stories.
The Pens, Kings, Hawks, Bruins all had them. When Sid and Geno were young, every year the Pens management surrounded them with different veterans to learn from--Lemieux, then Guerin, then Hossa, then Recchi, etc. One after the other, the Pens kept bringing these guys in. The closest the Leafs had to this were Marleau and Hainsey. Who do they have now?