Good ol' Bethesda. Much like Rockstar they don't seem to like bothering with PC much.
Although, I still hold out faith on Rockstar with the GTA V release soon, from their boasting, it does seem like they've used some of the money in that swimming pool to hire a decent set of programmers.
If at any time a hardware switch happens, be it consoles or PCs (There's a comparison joke here somewhere), Bethesda always seem to be the first to complain. I'm not entirely sure how a company with such a strong IP line-up and ever-growing fanbase can be so poor when it comes to caring for them.
The immediate jump out to me is the recommended 4GB of VRAM. That says to me that they've made these for the newer consoles and really can't be bothered to do much else for a PC port. We've seen something similar with WatchDogs and AC4.
Graphically, the game doesn't look terrible, but it doesn't look all that demanding either.
It's difficult not to love Bethesda's titles, but they've always been pretty poo when it comes to bug-testing.
I'm putting this down as either over-estimation or general bad porting.
(Did they even feel like listing which generation of i7?)