Playing instruments. I am extremely happy there is a Bards' College at all, but please give them a little more love.
This. You see musical instruments everywhere, yet only the npc bards can use them. I'd also like for the Bard's College to have more quests, to make it feel like an actual guild. Solitude could use more content, being the biggest city and capital of Skyrim, yet has half the content of Whiterun.
I'd also like to see the giant mudcrabs. I'll see the skeletons of large mudcrabs here and there, but I want them to actually come to life and attack.
The unofficial patch also needs to be made official.