This series is about fluffy slice-of-life-with-swapping stuff. It's never going to have a plot, although Natsuko's increasingly strong blushes whenever the idea of her and Haruko becoming a couple is brought up in some way suggests that romance may not be entirely out of the question. But the point of the series is the lighthearted fluff, not the progression. If you can't enjoy fluff for fluff's sake, this isn't the series for you.
I love the fluff, and I loved the swapping concept. I'm not saying the story is bad or anything. It just... I don't know, I wish there was development of some sort in the story. Personal opinion, of course. Thanks for the reply.