Great analysis! Oh, how I wish Seungho will slice Tarzan into pieces after dragging him to his courtyard so Nakyum could see him die and feel relieved (although Nakyum will probably be even more traumatized because he hates violence overall). But like you said, there's low chances that jerk dies since he is fanservice. Don't you think SH could let Nakyum leave with his sister? I believe he would and then NK will stay... or he'll leave and then return. I just hope we won't see make up until many chapters from now. They both need a mental break.
Of course I would love to see Seungho telling Nakyum that he can leave if he wishes but I wonder if we can really expect for that yet.
I feel Seungho reaching this point would mean he has learned to put Nakyum's wishes above his own, that would be the moment his love has taken over everything else he is used to. Seungho surely still loves Nakyum and this feeling is new but it's like a kid loves his favorite toy, he wants to own it and have it at his disposition. He is possessive. He knows he can't live without it and his feelings are priority. It's the selfish love of a kid. We are all waiting for the stage where his love becomes whole, the kind where Seungho instincts become to make Nakyum happy even if it means he himself doesn't get to be.
Maybe this is the turn point, let's hope.
Who was thirsty for the comeback of soft Seungho towards Nakyum?
I should stop predicting shit on this story since I usually guess wrong but as much as I wish for Seungho to fulfill his promised role as murderer, I doubt very much either Jihwa or the hobo assassin will pay for the kidnapping. Reason being that the hobo assassin is a fanservice character created to give smut with Jihwa and this arrangement alone grants them immunity from death in the trope.
I think it's more probable that Seungho will end the season bleeding in the snow in a battle with the unwashed version of him than actual harm come to either of the newly formed couple. This also would serve as some kind of 'justice' to feed to the readers who want Seungho's blood sacrifice before he is allowed to turn human again for Nakyum.
If I had my wish, Seungho would wreck havoc in the town, cutting the Tarzan's head off and stringing him up to dry in the sun and Jihwa, well, somehow I think Seungho can't quite get himself to actually kill Jihwa but he probably could get close to it.
On the soft side, If I had my other wish, I would want Seungho and Noona to interact more and have his patience tested. It doesn't seem Seungho had a female presence in his life, even less one assertive one. it would be fun to watch Seungho try to be soft and obedient to Noona for the sake of Nakyum and even maybe learn something from Nakyum's upbring.
Anyway, I believe the author herself must feel by now readers are getting worn out waiting for all that teasing that they see in her official art and here is hoping shippers starting getting feed instead of starving and eating crumbs like Seungho quiet reckoning that he fucked up big time and he needs to step up before Nakyum decides to leave for real.