My main gripe is that, according to some of the comments, a Microsoft account will be required, at least for the home version. It might seem like nitpicking, and perhaps many people wouldn't consider it a major hurdle, but if I'm paying for an OS, I like the idea of it being a product and not a service, especially if it's paid for as a product. Tying logins more strongly to online accounts also sounds bad from a privacy perspective, and I'd like any online services to be there only if I need them, not pushed to me as a necessity.
Essentially, I want the core software on my computer to just provide a working environment for me and my applications. I don't want it to be an entire online system of services the vendor wants me to want. Helpful additional services are nice, but none of it should be required for a product to work.
I'm also not fond of the idea of having to explain to my elderly parents why they need to register for yet another online account with yet another litany of terms and conditions just in order to use their computer.