I would think it would perhaps make more sense to run Africa akin to China in anniversary then.
How about this for a rule:
Scramble for Africa
During a powers collect income phase, it may, instead of collecting IPCs for it’s African (colonial) territories, immediately use it’s total IPC’s on Africa to purchase and place infantry units on any of it’s original African territories. Infantry placed in this way cost 3 IPCs. Remaining IPCs from African colonial purchases are forfeit.
Infantry placed in this way must be mobilized on separate territories (all purchased units may not be placed in the same territory)
A power may purchase/place no more than it has original territories controlled
Example: Germany controls 9 IPCs worth of African territories, but only controls it’s original territories of South West Africa and German East Africa. It may only purchase/place two infantry in Africa.
Addendum: Germany receives an additional infantry in Kameroon to start the game
Germany is getting a cruiser in SZ 24 in update 1.3 by the way