What's surprised me, coming back (obliged to for work) to MS Windows after 15 years away, is how the WM can't even put windows back where you left them, nor do basics like "always on top" (I swear, even recently, it used to do that; but it's application specific now). And how in generally great tools like OneNote you can't rotate a page printed to it (there's a workaround though, snip the page as an image [it's already an image!] then you're allowed to rotate), nor is there grouping of selections (ink in particular).
Third party tools have fixes for all this, and more.
These all seem like pre-1.0 issues to me.
