I honestly like harem + sharing. But it may not be for the same reasons as the previous guys you talked to. I like various aspects of nts, but if I had to narrow the single thing that gets me going the most, it would probably just be the naughtiness -or sluttiness in some cases- of the female characters. That's probably why I like female protag games too, the corruption and stuff. I know that's not the cup of tea of everyone.
For the typical harem + sharing, outside of that previous aspects I think there's two more aspects I like. For the dominant guys sharing some of their girls like in Desert Stalker, I think it's the sense of superiority (paradoxally) and for a game not focused that much on sharing like this one, the feeling of going beyond the limits of what is "acceptable" (for vanilla gamers). I don't like limits in games, that's probably why I'm very flexible about what I like in NTS/sharing and probably why I don't like to put stricts vanilla rules on nts itself: I don't mind humilation aspects in nts to some degree, as long it's not in every games. For variety. Idk why, but when I feel a nts game tries very very hard to put limitations one way or another, like "oh it would be too far blablabla", I start to enjoy it a little less.
That's the reason why I also like (amongst other types) the type of games you seem to enjoy the most (from you description in that post), those that are nts but edgy enough to be on the verge of ntr. Games in which you sometimes don't really know for sure, for a moment.