Let me explain with numbers: in a game with Vanilla and NTR, it's very annoying when you need 1000 points to even get a BJ from the LIs in the vanilla path, when the same LIs require 0.001 points from anyone else to become cum dumpsters in the NTR path. You want to make an NTR path? Fine, be coherent: either the LI is a though nut to crack in both paths or a cheap whore in both paths.
If you have to make an NTR path just to depict a whore that enjoys humiliate the "boyfriend", then better to create a game with a female MC that you can play as a whore.
I mean I get what you saying however I will say you comment feels random as fuck to me. As it has nothing to do with why I like the genre from what I was saying or why I disagreed with your original comment.
But I also disagree with your statement , I don't think a vanilla and NTR / NTS path need to go at the same speed at all unless the LI is a virgin but then NTR would make even less sense to me as it would need to be a slow burn corruption process or something similar. If you have lets say a party girl LI that is open minded I think it would make sense it doesn't take as long to do NTR content with others if the MC is into it and has her trust at least for a sharing path.
But also what you said also doesn't really make sense at least to me. Because most NTR / NTS games I've played the LI is already a wife or girlfriend. So there is no need to gather points for a BJ or whatever most of the time anyways as they have an established relationship usually. There are rare exceptions that but they aren't common at least from what ive played. So the speed of a NTR path usually comes to how into the fetish the dev makes the MC and how open the LI is for sharing. The better NTS games for me it comes down are for sure the slower paced ones as when they go to fast they rarely work out that well and usually are more or less guilty pleasures for fun / a game for the lewds.
I can't say much for actual NTR / cheating as I mostly only play sharing games when it comes to NTR content but id imagine the pacing of it should be about the same as a sharing path unless there is a narrative reason for the LI to cheat.