A few points on the OP. first off, it isnt a bad strategy, but there are some trouble spots:
Axis counters –
1) When I am axis, you should be very wary about landing in alegeria rd1. I like buying a German bomber in rd1. this alone should make an African landing r1 too risky. I can hit sz12 with 4 fighters from france. 1 fighter 1 bomber from Libya. 1 bomber from germany. This typically wipes out the allied navy of 4 trans, 1 dd, 1 bb with a lose of ~ 3 fighters. Well worthit for Germany. UK, will have trouble replacing capital ships, and will never be able to replace the battleship. I have also been known to do things like move the baltic fleet to sz7, move the med fleet west time to time. All these things should deter a r1 landing in africa.
2) Your strat never calls for buying capital ships. As I have said above, i buy an extra bomber with germany, and can buy a few more fighters as well. this air force will make shuttling troops to europe tough on you.
3) Ignoring africa is a mistake IMO. The Continent of Africa is worth 11 ipcs. If the allies want it, the Axis cant stop them from owning africa. So you are sacrificing a 22 ipc swing in your games, because you are hoping for a quick knock-out punch on berlin by r6. You wont knock-out a good axis player by round 6. ESPECIALLY if you are allowing Germany to earn 50+ ipcs/turn.
4) If you move into EE on r5 on my germany with force, i gurantee you can can take that force out. There is no way you get an uncounterable force into EE on me by r5.
USA alternatives –
The US can choose to shuttle troops to the North or the South in the Atlantic. It depends on what you want to accomplish, and how things in africa are going. I do think that ultimately, its on the US to ensure africa is secure. Sometimes that wont take much effort, maybe the first three rounds you will have enough gear in africa to secure it for the allies. So at that point you can switch to going north if you prefer. However, I have found games in which the USA bases it operation in north africa/med, and the UK bases is its opertaion in Karelia/Baltic, this puts max pressure on germany. If you have both the US and UK in the north, you certainly have 1-2 punch potentially that makes Germany have to guard WE/Berlin/EE. However, if you have US navy in the med, Now Germany has to worry about SE/Baltics/UKR as well. Now Germany cannot do much but turtle, cuz they cant send alot of force east to russia without leaving themself open to landings in all of their originally owned territory. And SE is big. The germans cannot afford to let the amercians hold that more than one turn. If the US gets to build 6 tanks there, Germany’s days are numbered.