Oblivion ended up feeling very much like Gothic 2 to me. Just a bit of background-- I never played Gothic 1 nor any of TES prior. When Oblivion developers were touting radiant AI, I was thinking that I had just seen that already in G2. Same with the combat. I prefer some of the gameplay elements of G2 vs Ob. Such as being able to choose only one Guild (not all). The fact that my thief/assassin was able to rise to the top of the Mage's Guild in Ob without having anything higher than a 10 in any of the core magic skills is silly (yes, there are mods that fix this).
I also prefer the G2 method for leveling. To me, the idea of an RPG is that I can perform actions that give me some kind of reward so that I can advance my character as I choose. In Ob, I feel that I am forced to play a certain way in order to increase certain skills. I like that Ob offered Trainers, but I like Gothic's use of Trainers better. I also liked how there were places in Gothic that I just flat-out needed to avoid, knowing I was nowhere near strong enough. Whereas in Ob, everything is my level (yeah, mods to fix this too). I hear G3 may have some encounters that have the same level as the player.