You had me until "It was Oblivion without the good questlines."
You could argue that Oblivion has one single good questline. That's it.
But yes, Gothic 3 even with community patches is still severely lacking.
Oblivion had only 1 good questline, the Dark Brotherhood. Everything else in that game was nothing special, and to be honest, even Dark Brotherhood wasn't really that special, but most nerds were like 10 year old at that time and were impressed so they don't stop fangirling about it.
But yeah, Gothic 3 managed to be even worse shit than Oblivion, and that is an achievement.