Gothic 3? Are we even trying today? Or did I miss a (quite sensible) caveat, earlier in the thread, that we were going to focus on games that had some sort of promising element or other 'reason to expect better', instead of just plain broken games?
Even with such a caveat, I'm genuinely interested in why you'd rate G3 to be obviously worse than Oblivion base-game. Let alone all those U3 clones that came out on 90s shareware, which had about a 1 in 10 strike rate in terms of not being flat out broken. I mean, G3 even has a working quicksave, and it's at least theoretically possible to avoid game-breaking bugs and play to the end. Hell, there's even more than one enemy type!
Ok, putting aside that kind of stupid sh**t as being the 'Steam Greenlight' of its day, is G3 really worse than Arkania? Again, not mocking, I'm genuinely interested in hearing out why you found Arkania (in the same series) more tolerable.
Even sticking to AAA, there's the Pools of Radiance remake that on top of being generally shit, had a bug that wiped your fucking hard-drive. And whilst I didn't hate Ultima 8 as much as some folk, any sympathy that might have put it ahead of G3 was lost the 2nd time it corrupted my operating system (sadly, that was 1 less than my total number of attempts at that game - my old man's computer techie had even warned me that it was U8 that was doing it, and went to the trouble of making a rescue disk for my old man to use after I'd quietly reinstalled the game and wrecked another Win 3.0 install).
If we're just looking at 'game as game', and forgetting the bugs, then there's a tonne of dungeon crawlers that sink lower than any 'full' open world quest crpg like G3. Not because the genre is intrinsically better, but simply because they're easier to shove out the door by putting a knife to all the unfinished enemies/maps/skills/classes. In the C64 days they wouldn't go to the trouble of changing their box material or game manual either; almost like they were specifically aiming to crush the souls of any kid at that age where you're just old enough to be massively excited by all the promised features, whilst not quite being worldly enough to realise that the developers had dumped a turd on your face before spending the next 70 hours trying to find the promised features, determined that you'll unlock the class requirements or 'get to the good part'.
Also see: 90s ports of any crpg or sports game, where they wouldn't mention that they'd cut 95% of the game's features in order to fit it into their shitty we really have sunk that low that we're knowingly defrauding children "101 games on 1 disk", and that you already own the other 100 games because 80 of them are really just one "only 1 game screen hence doesn't take up any disk space" D-grade Asteroids clone, and the other 20 are the same crappy shareware games that were given away free with every edition of your local gaming magazine.