Well, We'll have to wait for a Steam update to solve these problems...
I've been having these issues lately, almost constantly. Missing textures, bad shadowing, textures scaled down, stuttering, lag, freezing... Much more... It really has killed the immersion TESV was supposed to give. I wouldn't be surprised, however, as Oblivion was similar when it first came out.
The problem is that these games are optimized to run on 6 year old console hardware(I'm sure almost the whole community is aware of this).
I had bought a HD 6950 to max out this game.. After playing it and seeing reviews, I saw that my GPU didn't perform any better than the HD 6950 or the HD 6870... Pretty upsetting. Well, after getting fan-based patches and mods to improve the game's performance, little changed.
In conclusion, we'll have to suck it up for a while, until Bethesda decides to look back on its PC roots and give us something to really enjoy.