That’s a reasonable fear! There are so many manga series that lose sight of what made them appealing in the first place and get waylaid in dull diversions. This review was written last year when there were maybe ten chapters out. A year on, I’m still enjoying it as much as I was initially.
I think you’re right in that the underlying joke (and premise) still works, but I would say that it’s already started expanding the cast and relationships. Yet it feels natural, and not superfluous, because they all relate back to the feelings of the core cast, and thus deepen them a little more. Especially the school side of things, it lets the mangaka explore Anya being a kid and it mines her young perception of things for comedy. It’s still very much a comedy based on the characters’ attitudes and personas. Which hopefully gives it greater longevity.
Thank you for reading and commenting!