A Bound Armor/Shield conjuration spell, maybe linking it to the Mystic Binding perk like the weapons to make it stronger.
A First Person view when you're riding horses. I have no idea why they got rid of it from Oblivion. It's... kind of odd.
A First Person Werewolf View, this one is likely more difficult because it'd need some new models for First Person claws, but I still think it should've been included from the get go, it was there for the Bloodmoon expansion, and I loved the whole werewolf thing in Bloodmoon
