Morrowind is still the best, but Oblivion remastered made me enjoy it a lot more. The original Oblivion is such dog shit in so many ways, and a lot of that was due to how fucking bad the gameplay was. A lot of the changes in the remaster were for the better.
>Level scaling is less insane, ramps up in a much better fashion this time
>Level ups aren't stupid and actually gave you the stat points to get stronger without doing weird min/max shit
>Endurance was changed so you don't need to rush it
>Movement feels better, animations no longer awkwardly lock you in place
>The added sprint makes acrobatics and athletics feel even better
>Short swords scale with agility instead just to add more variety
>You get points towards the next level with all of your skills
>Magic schools level up faster by using spells that cost more magicka rather than spamming a 1 magicka spell constantly
There's probably some other stuff I'm not thinking of, but the actual game part of Oblivion was vastly improved and you can get the fuck out of my face if you somehow think the original is the better experience.

Right now it's like this:
Morrowind > Oblivion Remastered = Skyrim > > > > Oblivion