it is very hard, you need to make animation and difficulty rating for every, literally every surface in the game
It would only be as hard as the devs chose to make it. Some of them have done it before in Daggerfall, and others have done it before in several other games, notably Assassin's Creed. I'd expect they'd aim somewhere in the middle.
I know some people have this idea, when confronted with ideas about what Bethesda should include, that if they can't do it the best they shouldn't do it at all. I don't agree with that position, because frankly there is very little that they are the best at, besides making an open world game with freedom of choice. They don't have the best combat, or the best magic or the best stealth gameplay, but they allow you to do all of them, and of the games that do the same (Dark Messiah, Gothic) I think they are more polished or have other levels of complexity.
Basically, Skyrim is trying to have the best dragons and dragon fighting of any game to date. In order to facilitate that, the combat, magic and stealth still have to be pretty good. But I wouldn't want to leave out Speechcraft and Smithing/Crafting just because they aren't as expansive as other games, or as central to the main theme of this one. Same goes for climbing, horse combat, water travel, etc etc. Obviously the Devs have time constraints, but they should feel free to include features which are somewhat imperfect. If they aren't necessary to begin with, it won't matter that they are static and unpolished, and if they become popular in their truncated form, Beth can then expand on that idea and use the lessons they've already learned. That's what I really want to see them do, is innovate new gameplay we haven't seen before, rather than just streamlining the content we already have.