Default keymappings are one thing, and the inability to change the "button help" graphics when you remap a key is a (relatively) minor issue. Where the UI fails is mouse/keyboard sensitivity.
I do wonder about people saying they have *no* problems with the interface - they just say "I have no problems" and when I've asked they never answer specifically that they don't have the *specific* problems that we're talking about, I think most of them aren't even using the mouse in the menus (sometimes they keyboard doesn't even work properly).
And all Bethesda has said about it is they probably won't be fixing it (per dev comments in UI threads earlier).
Unfortunately, since they don't have anything else to say about it, almost everything here is wheel-spinning and recriminations, because among other reasons, the tech support forums are full of people who have no problems but rather than play the game they'd prefer to have arguments in the forums. So much progress is made that way.
I hope the CK helps people, but from the dev comments it looks like the worst problems are harder to fix than that (the modders are working with the flash script they used for the interface, but that doesn't cover everything that causes issues. I think it will finally require a "total interface conversion."
Personally I find the interface problems (inconsistency of confirmations, inconsistency in menu item selection, wrong item selection, etc) to be extremely annoying and a constant interruption to gameplay. They could be "fixed" (partly) by switching to a controller, except that I'm not satisfied with the way controllers turn and aim. That's just as bad or worse, for me, as the interface problems for mouse+keyboard.
Should have waited, checked the forums. Pre-ordered, foolishly.