I'd like to see mods like
1. Mixed races in Character Creation. It'd be nice to see what a Khajit/Nord mixed character would look like or The Lizard/Nord mix. It is hard to believe that in a world with such a broad spectrum of species, there would be no mixed breeding.

2. Magic/Melee weapons. One handed or two handed weapons who's power attack throws a ranged wave of energy based on the enchantment of the weapon.

3. More armor and weapon mods. There is just a lack of armor and weapon designs.

4. A pet dragon mod. Would be interesting to have a dragon actually be an ally and fly you from place to place. Yeah it might be OP in the open world, but then you could make dragon nests where you would have to fight 2 or 3 dragons at once. And you wouldn't be able to bring dragons into dungeons or near towns.

1- More interactions with your spouse.

2- Be able to carry a bedroll with you, so you can make a campsite to pass the night. (Kinda like the Red Dead Redemption campsite, but with no intention to fast travel.)

3- Better Inns ( The inns looks cool, but all of them feel the same, in both appearence and NPC's. I wish that the Inns could have more variety on the inside "decoration" and also could have more people inside drinking and singing and some of them could be drunk enough to challenge you for a brawl.).

1-5: Something like Real Time Settler mod from fallout 3.
You could build a settlement, town, or a huge city. Like adding walls and houses, shops, barrigades, castles or building some towers, or markarth like city from stone walls and blocks. Then recruting some citizens and set them to be guards or work at sawmills, shops, mines, just hang around or be beggars. You could also defend your settlement from bandit raids and stuff.

doubt i will see them, but im sure there are pros out there

Total conversion mods
pokemon in open world TES style
Lord of the rings in TES style
someone remade morrowind with oblivions engine or something, i would like to see cyrodil and morrowind again ( even if lorewise it makes no sense to have the old cities and stuff)

stuff that would be k
cheese shot from bows instead of arrows
"stop right there criminal scum
add weapons like flails spears and crossbows