Don’t see much wrong that he has done unless you blame Yzerman for lottery luck.
Yes, the Walman trade was bad- I can’t imagine Grier would have passed Walman on waivers given the state of the defense- we’ve since added Ceci and Liljigren as well. Maybe going for Debrincat was the wrong timing, but they didn’t give up too much and got a young first line winger who grew up rooting for them. He’s hit on most of his early picks- Seider, Raymond, Edvinsson, ASP, Danielson, Cossa, and MBN have proven good, or look like very good picks. Kasper looks solid too.
I believe your rebuild hasn’t started until you get an elite center or elite dman. Centers are almost exclusively found in the top 3, usually top 1-2. Elite dmen can be found elsewhere, as they did with Seider. Larkin-Danielson-Kulich could be an excellent center by committee, but Larkin isn’t that game breaking talent, and by the time the kids are ready, Larkin may be falling off.
The only way they could have gotten the elite C is to tank hard or get lottery luck. Maybe if they'd not gone for Debrincat and then tanked hard in 2023 and gotten one of the big 3, or Smith, but they’d have needed to be much, much worse give. How poor Chicago, SJ, Anaheim, CBJ, and MTL were that year.