This is only really applicable to mixed use stations, but the ability to change the display order of handled products would be useful. This would allow players to change the order to match station modules, or to sort/group products in the GUI by priority or cargo type for example.
My reason for suggesting this is entirely personal,. i use empty station modules a lot for placeholders, meaning when i rebuild them station products aren't always ordered in the same way the modules are, and that just slightly annoys me lmao.