i think having a belt type thats faster than the others would be nice to have, could obviously speed up things, but if you have a lot of items on a normal belt and it gets on a faster one, its not as cluttered (ive had problems with suchs large amounts and sorters), of course if it makes things too easy or something, maybe only make it exclusive to regular belts, instead of also walled and rollers, but id just like to see that added, on top of that, it would be nice to have something to move items upwards other than the sloped conveyor, would allow for more compact layouts, and last but not least, maybe an option in the menu such as you can turn all auto-miners on/off, you could have something that stops all the belts, its annoying to wait for all items to pass or have to change something while theyre passing sometimes, so quickly pausing it for a moment could make things easier
(ps: i know there is one guideline here, but there are so many suggestions and it would take very long to make sure i have something new, so as another suggestion, you could allow it so its more obvious what kind of ideas are suggested more so you know what the players want most?)