When I played Oblivion years ago, I got bored quickly, but I think it was because I ended up focusing on the wrong things. Knowledge of how the level scaling worked led me to having an overpowered character, and closing the Oblivion gates was repetitive and mostly easy because (IIRC) I could just run past most of the threats.

I heard later that there is a lot of interesting stuff to discover if you ignore the main quest line. I would like to try that some time, and it would be pretty cool to do it with an upgraded game engine & environment. Here’s hoping this project gets the volunteers it needs.