Single-handedly fighting the whole corrupted bunch of altmers that are the Aldmerei Dominion. With just some massive fireballs and a quiver of daedric arrows, the combo I will always rock.....
Paarthurnax...just no.
A weird, corrupt human version of Boethiah sporting some massive smokey black battleaxe, like some sort of God of War end-game boss Hades, God of the Underworld, type thing would be pretty cool awesome amazing BADASS.
For some reason I loved Oblivion, where you don't actually fight the final boss because Mehrunes Dagon is way out of your league and the only way you can save the day is by helping Martin transform into a Divine. It'd be fun to have something along those lines, but with a little more player input, like you have to solve a dwemer puzzle to activate a huge automaton to fight an ancient powerful magical being or something.
Alternatively, an epic battle where you lead troops and slaughter dozens of Thalmor or something, like the end of Fallout New Vegas, where there is a final guy you fight but it feels more challenging getting there and your choices throughout the game affect the outcome
I love being a protagonist that is pretty badass but still uses his brain to solve problems, most "slug it out" type boss battles are just really disappointing. My werewolf one-shotted harkon, sad times
Agreed with the epic battle. How badass would it be to lead an army against the Dominion, not just be part of it like in the Civil War questline. Personally, I think that the appearance of a Dragonborn in the game after Oblivion, in which the last Dragonborn Emperor dies, is no coincidence. I think the next game will be a direct sequel, but based in a different area, and will see your Dragonborn crowned as emperor.
I think it would be great if the game developers could used the save files to make your current character the main boss in the next game and if you don’t have a previous save, a randomised final boss so that each time you run through the boss is a different race and has different powers, shouts, abilities. I think there is nothing worse than facing the same boss with the same abilities each play through. Perhaps a undead version that you have to quest to bring back to help some sort of disaster, only something goes way wrong and then its "meet the evil former you".