It's not reasonable. That's a psycho that paid for a product, got what they paid for, and now want to extort the developer for extra features instead of paying more.
The question is whether the missing feature could be reasonably inferred to be present based on competing products or the product’s description.
Let’s say I buy a camera. It takes photos well enough, but I soon learn that it can only transfer the photos to my computer over WiFi or the cloud. This is terribly slow and not in-line with what I’d expect from a camera, so I leave a 3 star review saying that while it works fine, not being able to transfer photos quickly means I cannot recommend it, and that if this feature were added in a software update I’d rate it 5 stars.
Imo this is totally reasonable and a review whose contribution to the average rating I would value much more than “5 stars, the photos are good. I’m upset however that I can’t transfer them quickly, but oh well that’s a missing feature and I’m not allowed to complain about missing features in a way that affects the star rating because that would make the people who didn’t implant them upset”
On the other hand if I leave a review for the camera saying “3 stars, this did not come with a exposure and zoom configuration that let me capture the andromeda galaxy, please add and I’ll make 5 stars”, that’s a whole different story.
Let’s say I buy a camera. It takes photos well enough, but I soon learn that it can only transfer the photos to my computer over WiFi or the cloud. This is terribly slow and not in-line with what I’d expect from a camera, so I leave a 3 star review saying that while it works fine, not being able to transfer photos quickly means I cannot recommend it, and that if this feature were added in a software update I’d rate it 5 stars.
Imo this is totally reasonable and a review whose contribution to the average rating I would value much more than “5 stars, the photos are good. I’m upset however that I can’t transfer them quickly, but oh well that’s a missing feature and I’m not allowed to complain about missing features in a way that affects the star rating because that would make the people who didn’t implant them upset”
On the other hand if I leave a review for the camera saying “3 stars, this did not come with a exposure and zoom configuration that let me capture the andromeda galaxy, please add and I’ll make 5 stars”, that’s a whole different story.