-Miraak's mask having the most generic enchantment ever.
That's definitely one of mine...
Also his sword having a slightly less generic enchantment.
-No closure on the Thalmor conflict.
-No closure about the Dwemer.
The Thalmor conflict is going to be a multi-game thing, that is obvious
The Dwemer have been a mystery since Morrowind, it is unlikely we will ever fully know.
Me:
-most of the "Artifacts" being worse than basic enchanted armor.
I hope we never get closure on the Dwemer, and the Thalmor conflict is being saved for TESVI: Hammerfell.
Some of mine...
Wow, those are all guild related. Funny how that works.
Edit: Bonus Round!
The civil war being tied to the main quest is still the thing that bugs me most about Skyrim.
This, and the entire College of Winterhold quest, and the way magic is in general.
Being forced to join the college I hate, I usually go straight to Septimus. And I completely agree with your last point. Bethesda didn't really make your race matter.
I do too, if only to avoid point #6, but I won't deny that it totally kills immersion (and I'm a huge roleplayer - my characters don't just run around doing stuff that I know is advantageous to them if they wouldn't reasonably know).