My real concern is that figuring out so many things without the GUI is currently a real PITA. Like trying to make IIS act as a reverse proxy. It's a huge pain, and most of the docs are telling you to click various things. Compared to setting up nginx, ouch. Compounding things is the fact that MS took a cover-our-ass policy to installing things, so even after installing IIS, you've gotta go explicitly install "dynamic" compression as an extra. Then to really make it work, there's a file buried in system32 you've gotta edit, because you can't configure those settings by default at a site level. Overall, it's just way more complicated.
I know they're working on it, and PS is a great shell overall, even if it is missing a lot of simple tools by default.
But MS is way late to the party. OpenVZ was in heavy use what, a decade ago? And MS did nothing to respond, really. But hey, maybe they'll pull it off. I don't have a fundamental objection to Windows.