There's really only one setting in TSW that consistently annoys me: the choice between miles and kilometers. Since only one system applies at a time, I'd really like this to become an automatic setting that can be changed if for some reason one prefers looking at peculiar measurements.
I myself would also like to see the measurement system be automatic to the route you choose to play. Trying to remember to change it back and forth is a pain.
It should definitely default to the correct unit for the selected route when it loads and if you want to force it to use the other, you can still do it through the settings menu. I’ve only just started regularly driving the German routes and it’s becoming a drag having to change it or check that I have the correct one selected when I first start the game.
I forgot to mention another annoyance: forgetting to press E to confirm the measurement system change I've selected!