Gothic 2 was also a lot better than it's better looking sequel to be honest, although Gothic 3 looked stunning, the game itself was 'dumbed down' in the same way as Oblivion, certainly, charging an Orc in Gothic 2 without a LOT of heavy armour, experience and a good sword, would get you very dead very quickly.
As for Oblivion, I've got The Knights of Nine and Shivering Isles expansion packs, Shivering Isles certainly adds a good amount of new content to the game, Knights of Nine is less inspiring but still an interesting storyline. My biggest complaint about Oblivion is levelling, choosing Alchemy as a main skill will mean that you will advance very very quickly in levels, however, choosing Destruction as a main skill means that you will advance a lot lot slower. You can basically choose a character with Mercantile, Armorer, Security, Blunt, Heavy Armor and a few magic disciplines, and it will take you absolutely forever to advance to any significant level.