Gothic and Dark Souls have nothing in common. The great joy of Gothic series is the fucking BEST exploration ever made in a game, and tons of great options to solve quests and do stuff. Dark Souls highlights, on the other hand, is the wonderful combat, the atmosphere and the world & lore.
i disagree that they have nothing in common. at their core, they're both "open world akshun arrrr-pee-gees", and while Gothic does the more traditional side of rpgs better (as you mentioned, the quests and solutions), DkS's "akshun" part is multiple orders of magnitude better (by itself gothic's combat (and encounter design) is serviceable at best, and when compared to something like DkS or Dragon's Dogma or, satan forbid, a "purer" action slasher game like Blade of Darkness (a PC exclusive from almost 15 fucking years ago, for satans sake!) or DMC/NG and their ilk, it's abso-fucking-lutely horseshit. not even comparing Arcanum in TB to something like JA2 makes the difference clear enough). and while DkS is rather different in it's world design (the ever-present level-boss->level-boss "paradigm", and is relatively unique that way), because the "akshun" parts are so much better, the exploration feels so much more tense and rewarding so i disagree even with that part