I have following idea which would be useful mostly in multiplayer - player logos.
Player logo would add-on to player colours - and displayed in finances dialogue - instead picture of headquarters:
1. if it would not be built
2. if player would wish to see it instead picture of hq
3. if player would see finances of challenging company (or public services)
It would be in png format - like other game pictures.
Also player logo would be zoomed and displayed over some buildings - to show ownership of those buildings - because they would be a little better visible then. But this should be enabled (and then disabled) from display settings dialogue.
BTW:
TTD has colour and face
Transport Giant has logo and colour (few logos have own colour scheme; other logos have no attached colour and vehicles are displayed in original colours)
Industry Giant 2 has logo
And for this time it is all.
nice detail but not very needed
That idea is targeted mostly on making game a little more comfortable in graphics.