I just started playing again after not having played for a pretty long while.
The mouse sensitivity seems really off. Even at max, it doesn't feel like it's enough and it's really loose. When I stop moving the mouse, it almost feels like the screen is catching up to where I want to look. Was it always like that, or is something different?

I haven't messed with mouse sensitivity but when I turn to look behind my character really fast, things do look like they lag a little with loading. It's always been that way for me. Have ya checked for new mouse drivers recently? It could just be that's the way Skyrim is, seeing how the game is a console port.

So, they really did just port it from the console. That explains why it killed my arm all the time while I was playing before. It always seemed loose and cause discomfort, but it felt worse this time around.
Is there an easy fix to that? Like, could a mod come out that could fix it? Or would it have to be something Bethesda does?
Next time, I really hope they make if for PC first, haha. Or at least make the port over more... comfortable...

Go to \Users\[Username]\My Documents\My Games\Skyrim
Open the SkyrimPrefs.ini file with notepad
Find the line bMouseAcceleration=1 (located under [Controls])
Replace the 1 with a 0
Save the file (make sure you don't accidentally save it as Skyrim.ini.txt)

I notice a small difference. I'll play with it a bit. Hopefully, that fixes it!
Thanks.