The plot WILL eventually pick up, but this is Okayado's first serialized piece of work so i imagine that he's being forced to go for what sells currently, AKA ecchi harem rom-com, and the first tankobon sold amazingly well over the span of just 2 months. The last chapter, as i said, most likely just worked on introducing some side-characters, the series is not even a year old yet. Odds are that over the span of the next year he'll finish up introducing characters/giving them special chapters that focus on them(Like Miia's shedding chapter HNGGGGGGG) the plot, will pick up i imagine. The plot after all is that he has to eventually pick one to marry/couple it up with. Also Okayado is a total bro, he is all about healthy loving relationships, i can't imagine him dragging it on forever with no real progression(It just doesn't fit into what he's been known to make prior to Monster musume), so i'm hoping it picks up soon, but yea, it's a slow start.
I wish it would've just been all about Darling and Miia being lovey dovey, that'd have been the best for me, but i am enjoying it a lot regardless.
Also:
Deadman wonderland
Finally, mangaka got back to work after pregnancy. The chapter was kind of lackluster but i didn't imagine it'd be anything else after more than a year of build-up and anticipation, can't wait to see how it progresses
Also planning on ordering the two first volumes of Monster musume soon, was surprised after realizing how relatively cheap it'd be to import.
Not to mention that it's the year of the snake, Miia has to get good chapters and has to win, obviously. Next year is year of the horse.