We don't know what will be on the bigger unit display itself (but some people will still complain that they hide their unit away and cannot see it). The functions would ideally be split between things that you need for daily use (on device display) and occasional settings change (web/app UI).
Practically speaking, having an OSD comes with a great cost to serve a few OCD/legacy needs. If the OSD isn't an overlay on video content, it will look outdated. If it is an overlay, then you have introduced a need for video processing in the unit that adds to heat, cost and complexity and potentially impact noise/performance. People who prize sound quality should be thankful for removing all that processing circuitry. Better design for the future is to make that information be sent as meta data over the HDMI with the display being able to overlay it.
As we get into higher and higher resolutions, the old "VGA resolution" OSD starts to look very bad and dated. Increasing the resolution of the OSD non-linearly increases the amount of video processing needed just to accommodate it.
Adding any kind of interactivity to the OSD requires considerable low-level firmware that complicates updates and purposing buttons on the remote to do so (for example, just maintaining the context of where you were if the OSD is turned on and off rather than starting from the main menu which is annoying requires a state machine to be maintained). All these are solved problems, of course, but as the functionality increases, these things get way too complex with impact on updates, maintenance and support.
I would rather that all that effort went into the quality of the audio than serve a niche market that will take time to switch over out of habit. But a transition is never without protests from those who like the "old way".