As for suggestions, I would strongly recommend to do something drastic with the map, it is not only that the coastline is way off, or some cities are misplaced, it is also a question of playability because the location of mountains, railways, etc, play a significant role in strategic decissions.
Other suggestions I woyuld like to do in reference to SC3
-In SC3 the research system was very wrong, research cost was relatively high while upgrading units was relatively cheap, it should be the other way around, development should be time consuming but not resources consuming, while upgrading should be not straightforward, hisotrically there were lots of units fighting with obsolete equipment for the duration of the war.
-Regarding tank tech evolution, in SC3 tank units became so powerful that they were all purpose units, while historically tank units in 1945 were in general were in a weaker position in relation to infantry than 1939. Tanks in 1945 had better armour and more powerful antitank guns, but they were not better against infantry, while infantry OTOH exchanged the light AT guns of 1939 with heavy AT guns and bazookas like AT weapons.