I like what he's doing, mainly because he and Michael Stewart's Standing Ground are one of the rare younger designers who are designing something other than art-hoe cumrags. It's chic, sexy, desirable and with a bit more technical finesse to his tailoring, I could see him going very far.
For me, it's more along the lines of Gen-Z Helmut Lang/Hedi Slimane. That said, I'll argue that he seems to be more more in touch with the youthful cool vibe of 60s/70s YSL rather than the glossy monolith of the later years. I wouldn't be mad to see him helming the brand in 10 or so years.