Belt mergers would be nice, especially if they had a forced order setting like the splitters. It'd take away a lot of logic stuff with the gates and screens and whatnot, but having screens everywhere isn't that nice either
A mass select for destroying and maybe even copying buildings
A way to set a priority to funnels for when there are multiple accessing the same building's products
A shortcut to open the recipe to something in your inventory
An eyedropper keybind for selecting a building in the world to pull the building from your inventory
An indicator/selector for the screen when multiple numbers are shown, like in the "special" tab for the queen bee
Screen should be able to have a higher threshold than 1000, at least for targets that easily exceed that number
Range indicator for the hovering hand and forcefield crane
A setting for NPC to follow but keep some distance. I like having a 'companion' follow me, but with how they try to get as close as possible to me, it's a bit annoying