Display - Currently, most software does not accommodate the new aspect ratio. Games on FBontakte will be quickly ated, which is sad. When watching a video, there is still unused space on the screen. Corner rounding is completely unnecessary. Constantly lurching between extremes of brightness (high or low) is an annoyance caused by the automated setting.
The phone's camera sensor is from last year, and it wasn't great even then. Noise is removed by severe image processing methods, blurring the image in the process. Seen in the interior shot in particular. The nexus 5x from the previous year had a superior camera, as it was able to preserve a greater number of tiny details in its photographs (but was slower). On top of that, HDR is not reliable; whenever I try to capture the sky in a photo, something overexposes.
Everything works OK in terms of speed, however for some reason, 3 of the phone's 4 GB of RAM is always being used up by unnecessary junk. Thank goodness this has no bearing on the rate of travel.
No two-day battery life for this phone, even if by some miracle it were to appear.
Several issues with the design, the ergonomics, and the safety. This fingerprint reader is a total failure. When using it in a case, your finger will need to fit into the little hole near to the camera. Moreover, the "frameless" design's glass and metal components are easily broken without a protective housing. So, naturally, we over-dressed right away. In this particular instance, the frame sizes are already comparable to those of standard smartphones. The phone is awkward to pick up due to the rounded corners of the screen and the back panel (again, this is solved with a slip case).
Audio - mono only, please (which was in the nexus 6p, for example). It's not crucial, but it's pleasant when the speakers are directed at the user.
The amount of soft, unremovable garbage on the phone is significant, and some of it cannot be disabled. Together with an extraneous Bixby. Another thing that Samsung does consistently is make the system buttons small (I saw this with the s7 edge).