Again, not talking about Cities Skylines, but CITIES IN MOTION.
Also, a game where you have to build one city (CSL) or a game where you build a urban mass transit system (CiM) definitely needs a much lower scale than a game where you have to build inter-city transport (TF).
Anyway, I never complained about the map size of TF.
If the detail is what brings TF such poor performance, then pls, remove details. Gameplay is far more important than details.