I love both Fable and Oblivion, so count me out of that battle
The reason I suggested a Fable-esque oddworld game is because Im afraid an oblivion-styled game is too specific... There's a large amount of people who love these game, but there's also a large amount of people who hate the games because it's boring and too open. An oblivion-style game caters to too specific tastes. A lot of people love adventure games though, and I felt that Fable was more of an adventure game with RPG elements rather than a hardcore RPG with tons of things to explore, books to read and lore to hear.
Fable is much more simple, and It had a more linear story-line. To go from FPS to really just RPG'ish RPGs is too much of a gap, but I could totally see a fable-styled oddworld game come out at some point
Although personally I wouldn't mind playing an Oblivion'y oddworld game.