Some first-person shooters from the 1990s handled keybindings better than that. Either this is 2011 and that's the best Bethesda could do, or they just didn't bother to tailor the UI for the PC. I know which explanation I believe.
Also, the way some menus are laid out practically REQUIRES you to switch awkwardly between the mouse and keyboard buttons when navigating menus. If you try to use only the mouse or only the keyboard, you end up either having problems selecting and clicking everything properly with the mouse, or you end up having to reach over from the keyboard to use the mouse to click something (clicking "Yes" while smithing, for example). As well, having the mouse cursor anywhere near the inventory menu screws up what you're doing if you're trying to select things with just the keyboard, because the mouse and keyboard then "compete" for selecting things and scrolling the list.
There are many other usability issues with Skyrim's UI on the PC, from the favorites and spell menus to the perk constellation and everywhere in between. I've dealt with some pretty crappy PC UIs in my day, but this is a cake-taker.
Skyrim is great, but the UI is a sloppy, lazy console port that Bethesda spent absolutely no effort on. I know it, they know it, and you apologists know it, too. Have I learned to use this terrible UI fairly efficiently? Yes. Is it still sloppy and terrible? YES.

