As a Roblox developer, it is currently too hard to make UI that can blend with the CoreGui on the Xbox version of Roblox.
The popup menu that shows up when pressing the menu button is entirely uncustomizable, and adding topbar buttons to the top can look out of place.
If Roblox is able to address this issue, it would improve my development experience because UI would look more in place, and users have one landmark place to access infrequently used controls.
If this was added, adding a button that would be used infrequently, like a invite friends button could be under the popup menu instead of decreasing immersion and being always on screen.