But does that balance the game?
Transport ships will be used mainly by the Allies to encircle the CPs; the balancing factor should be the CPs internal lines allowing them to reinforce any front in a turn. But if these don’t exist…
Consider:
It takes the Allies one turn to ship units from London to Karelia; the only plausible threat being German subs roaming SZ 5.
It takes German infantry four turns to march from Berlin to Moscow, even assuming the way has been cleared of enemy units by previous waves of attacks.
This can be halved by taking SZ 12 and investing in a transport fleet, but even then the Germans can (I think) only stop Russia building new navy there by taking Karelia, with its large Allied garrison from England…
While the CPs have to laboriously slog their way over the map one tt at a time, the Allies can use their sea power to be pretty much anywhere they want to be in a turn or two.
@Croesus:
but I wish I didn’t need to houserule at all.
You don’t. I’m sure the system (as is) will work quite well. Transport ships should eliminate the “massive imbalance” issues of a lack of rail