You can at least disable team colours so everyone has a unique colour however I definitely want the option to choose colours for at least skirmish and custom games.
One thing I like to do is have one team as ‘cold’ colours (blue, green, cyan) and the other team as ‘warm’ colours (red, orange, yellow) this works well as it is easy in big games to quickly identify who is bad and who is good but also be able to identify individual players.
Currently in 4v4 the first team is blue, red, green and yellow which is a mix of warm and cold colours and its pretty confusing.
Choosing your colour is one of those things you don’t notice until its gone, I really hope this can come in an early patch.