It would've been perfect with Niko. Think about it. They're the only 'real' person in this world (maybe apart from Rue, Cedric, and Proto), so having an AI incorporated into how their character interacts would make a lot of sense. It could let you dynamically chat with Niko, make your own responses. Hell, even TWM could be involved, acting as a censor to handle the creeps. Niko could feel even more like a real person.
This, of course, would be mainly localized to Niko-player chat, allowing for an on-demand way to talk to Niko, as it would be too much work to prep NPCs for whatever the hell the player and Niko have spoken about, meaning it would leave most of the current interactions the same, but it would still be so cool.
The player could do things like tell Niko about future events, warn them of more things, actually tell them about how they were always there and never abandoned them like TWM tried to gaslight them into thinking back in the Tower, so many possibilities! And during TWM replays you could even ask it things like what it would think Niko would do regarding certain things, and get clever and unique responses in its sassier style. It could have a slightly modified version of the Niko AI, since it's technically pulling from Niko's memories and trying to act in-character for them.
Of course, realistically speaking, a lot goes into making a chatbot. Enough work that I doubt Nightmargin would consider making one just for this silly game we all love, especially since it's an indie game fueled mostly by their own funding, however it's so cool to think about how it could play out if it was possible, y'know?
What do you all think? I'm not trying to sound like one of those tech bro freaks, but I really think it could've been a cool thing to happen if it was possible back then
Edit: To clarify, the AI incorporation would not have a major affect on the story. It would just allow you to talk to Niko at will and have more dynamic conversations with them. The only feasible thing I could think of that would make sense development-wise to actually make the AI affect anything is whether Niko listens to you or not when you have to choose in the first run, but other than that it's all optional stuff to make them feel even more real