Ok looking at the map a few things…
I think the yellow for Japan and orange you got for UK are too similiar. I think you should go kaiki for england
I think USA should be drab olive rather than that hunter green you got. Its too dark.
Germany should be less blue grey and more field grey
Soviets should be earth brown or kinda of a brown green mix. Check out a picture of the Soviet soldiers uniform in WW2 for the exaxt color.
China should be a light green or the red you got for russia.
Italy is fine and Japan is fine.
Neutrals should be cream rather than white. White has the look of incomplete ( or lacking a color) I would recolor France and her colonies french blue so people can use the same map and play 1939. In that way they wond have the print 2 maps and secondly, the french are known.
I hope you have some neat rules for this.