I had quite forgotten this was the 200th story, and as the 200th story I would have hoped for something a little more than average. This is not bad, but not good. It has a couple of chances to elevate the tale and do something a little more interesting, but shies away from them in the most boring of ways. And it telegraphs other aspects of the story with all the subtlety of an American sitcom.
I have no problems with a story having no plot, but if you're going to do that, you need to really do something with the characters and/or set-pieces. By way of example, the fourth season story Midnight has absolutely no plot whatsoever, but it becomes totally gripping as it progresses.
Worth a look, and it has some nice ideas, but the lower you set your expectations, the more enjoyment you'll receive from it.