I'd prefer just a straight up scifi/cyberpunk setting over otaku version of modern Tokyo. Don't really care about the overuse of tropes you see in games with settings like that. I liked Souls games because they stood apart from your typical anime JRPG.
Using traffic signs as weapons seems like such a high level technique to use in real life.
If nothing else using a real life setting gives it a unique feeling of familiarity that is shown off in that fanart.
My exact thoughts when seeing these (excellent) illustrations, I absolutely loved the 10-19 floors because of the setting. This would be both awesome int itself, and a great change of setting for a Souls game.
Refine the glorious Let It Die gameplay to be more like Dark Souls (and less F2P feeling) and you've got this to a certain degree. Definitely would have me more interested than the fantasy shit that DS is currently set in. I mean, I love the DS games, but I don't care for fantasy too much anymore.
So yeah, do this right and I'd play it so so so fucking hard.