Bethesda got the money to do this. Do they got the time? Yeah, but maybe not for Skyrim. Bugs? All games have bugs, that's why it's worked out in development. Kinect? Why not? They got the time and money to do it, but Skyrim wouldn't be the game for it. TES games did follow what people would call "gimmicks" back in the day to impress an "obscure" fanbase. Betheesda can do it, it's all based on if they want to invest the time into it. They got the money. Me? I would prefer them shooting for a Phone App game more than Move or Kinect.
One tend to forget that Companies don't have infinite resource or infinite time, which is the case for Bethesda. Remember that the money would have to pay for every employee, every resource, every tax, every loans, every department, every labor, every rent, every copyright, and many, many more. The resource are all in a pit. They have to distribute it "equally" to pretty much everything. If they add in those motion control, expect some trimming on the other department just to have it. Also expect MORE money into the debugging department just to make sure these motion control is "playable".
Then we have bugs in general. Bethesda is one of those game company that should really be known for releasing bugged product that even rivals Obsidian. As I mention before if Bethesda is ganna add something new to a new engine, they would be gank with bugs left and right and finding them in a sea of codes would take a long time. That is less time spent on making TES less of a TES and more of a "casual" game that would hardly resemble what TES is, just to add in motion control.
As for the "TES games did follow what people would call "gimmicks" back in the day", I assume this would be the new Graphic Oblivion has? Look how well that went with the game and the fans.