1 - colour coding - When you zoom out the colour coding of production stage is nice, but would be better in my opinion if it followed a pattern, e.g. the colours of the rainbow, so Red fades to orange, yellow etc. this will keep areas quick to locate, and with a more gradual change of colours it will also highlight if anything is being done out of sequence.
2 - Shift click to place multiples of the same station
3 - you shouldn’t be able to select second tier upgrades before first tier upgrades, unless they do distinctly different things that make it a strategic choice.
4 - windows shouldn’t close when you select an upgrade
5 - option to install stations with all researched upgrades pre-installed, for appropriate additional cost. Time saving only.
6 - testing facility - the first car of any type, (or perhaps have this as a later feature as an option to help with marketing) should be put through testing, for safety, breaking distance etc. Affects the perception and sale price of the car.
7 - Mega resource conveyors - the motorway equivalent for resource conveyance. big, expensive, raised, for moving stuff about quickly, but not for directly connecting to stations. Currently there is little strategy for conveyors, so just thinking of have to add depth. May not be necessary.
8 - turbo charge stations - option to put them into overdrive. May result in breakages, malfunctions, injury, higher power usage, lower quality output.
9 - spare parts - requirement to produce some for the market - demand is determined by quality of your cars, if you dont meet the demand people cant fix their cars, and your reputation is reduced.
10 - research stations can only do research on the sections they can see/within range. Adds some strategy to where you place your scientists. Does limit research options however.