Good assessment! This manga (and many others these days) seems to be taking an "American" style approach to story telling. US based tv series have this habit of starting with a good premise, good cast, etc. The show gets popular and writers proceed to wring the shit out of it for about 3 seasons too long. Then it fades into cancellation with no one remembering it was once a respectable piece of work.
If this manga would spend more time developing the main-couple and less time having unpleasant characters sabotaging someone else, this could actually be really good...