Many of the 'blunders' of W8 that W8.1 fixes were centred around the introduction of the MetroModern UI interface, imposing a touch interface on non- touch desktop machines and deprecating the old desktop interface and start menu.

8.1 allows you to boot straight to desktop, and restores the Start button to that desktop - clicking it takes you to the apps listing screen rather than to the old start menu, but with the sorting options available (also new for 8.1) we're a lot closer than we were to a usable classic desktop. Some people will no doubt carry on running Start8, ClassicShell and the like, but I've made the transition and am finding the new interface productive after an adjustment period.

Right-clicking the start button brings up a list of shortcuts to various admin and other functions like Run, and also provides an easy route to shut down for those who find Alt-F4 too challenging.

I've used TIFKAM on touch tablets and it is fine, but it's a crazy interface for a non-touch keyboard & mouse interface. Microsoft were, with some justification, seen to be abandoning that huge user base in pursuit of the tablet market, and 8.1 goes some decent way to reversing that decion.

There are all sorts of other upgrades and tweaks under the hood, but I think those are the headlines on the 'blunders' front. And to save anyone the effort no I am not a 'M$ sheeple' or whatever the cool kids are calling it these days - although I do earn my living writing software for, predominantly, the Microsoft ecosystem.