Honestly at this point I think part of why UTY fascinates me so much is that it comes off a bit like Fallout New Vegas discussions where a good amount of it is discussing the characters and the morality behind them. Undertale simply created the foundation. The lack of closure with Kanako only makes it more discussable, similar to the tons of 'saving Asriel' fanfic scenarios on the market.
Though, that being said it's weird because I do consider UTY to be 'mediocrely written', its just that the scenario it creates and some interesting character beats like Roba's whole thing of putting Chujin on a pedestal really feels like a concept worth exploring more. There's just so much untapped potential. Martlet and Dalv felt underutilized, especially when Dalv is held up as 'the fourth' when he really did fuckall compared to Toriel in their segments of the game.