Yeah, I agree with everyone else here that being so shocked about the lack of much real isekai plot when the title literally contains the word "harem" and uses that word in the literal, dictionary definition sense is sorta stupid on their part. Ah, but what can I say? This is the Internet. Ever day, it becomes just a bit easier to use, and thus, every day, more and more idiots keep showing up.
They oughta make Form ID-10T an actual thing.
I will admit, it's a shame that this thing drags on the way it does, but at the very least it means we get a rich and highly detailed world out of it.
Also, it's kinda nice to see an Isekai story where there's nothing really earth-shatteringly-important going on in the world, and so the Isekai'd dude just settles in to live a good life and build himself a harem full of cute girls. You also just gotta love how it's turning out, too. These girls all come into Michio's possession expecting a tough (though not brutal) existence. Instead, they're pretty much made into family in all but name. Roxanne's reaction is pretty telling in that she would prefer to die if Michio dies.
That said, even though it can be pretty smutty at time (though for some of us that's part of the attraction) and there seems to be no major conflict at hand, it's a pretty nice story all the same. Really, this is just slice-of-life under a different genre.