Yes, I agree it should be easy to understand and to apply, otherwise it lengthens the round time, which is already pretty long
How about something like this:
1. round after battle, place atleast 3 units in the captures province, or the maximum amount you have left after combat
2. round decrease the garrison by one each turn
.... until you reach 1 garrison
This could be extended by differentiations on the theaters.
E.g.:
Africa 1 garrison
France 2 garrison (usually you have more than enough in france to prevent invasions anyways)
Balkan 2
Soviet Union west of ural 3 or 4
Soviet Union east of ural 1
America
ever seen an axis invasion?
This would be good distribution, but should be tested somewhen.
The idea of leaders is also very good, this somewhat defeats the point of super stacks.
If you engage the enemy with 12 vs 12 and manage to beat him the defender has 1d6 per lasting division to surrender
the rest may flee to a neighbouring province or has to surrender if they are encircled.
But what about an allied invasion ? They usually stack more than just 12 divisions at once,
a) its very easy to smash them and throw them back into the sea
b) you can t capture the province as german player after victory until you defeated all the allied units.
c) the allies may not attack with the units left in their round, thus have to reinforce their beachhead in order to hold it.
No more meching into Berlin if they engage heavy resistance.
One has to evaluate the impact on gameplay and how to adjust the VPs to counter potential inbalance