Would Demon's Souls count? Dark Souls is a spiritual successor, so I can't quite tell if that throws it out of consideration.
Otherwise, Xenoblade Chronicles! Monolith Soft poured so much work into this product. It's littered with sidequests and there's depth to pretty much every aspect of the game. Sidequests eventually lead to rebuilding a city. Talking to people leads to ranking them on an affinity chart then finishing sidequests can link people together. Every skill has upgrades, every character has a variety of skills, every character has a tree of attributes that upgrade over time.
And it's got good load times
Otherwise, Xenoblade Chronicles! Monolith Soft poured so much work into this product. It's littered with sidequests and there's depth to pretty much every aspect of the game. Sidequests eventually lead to rebuilding a city. Talking to people leads to ranking them on an affinity chart then finishing sidequests can link people together. Every skill has upgrades, every character has a variety of skills, every character has a tree of attributes that upgrade over time.
And it's got good load times