I hate doing this, but i'm going to blitz some of your idea's.
UNITS
Heavy inf: I'm not sure you understand how a WW2 infantry platoon worked, but I'll make it simple. In your average German platoon, at least two soldiers would have an MG34/42. This is due to 'force multiplication' and the Infantry carried the 'stormtrooper' tactics of the Ruhr Battalion from WW1
AA Infantry: This game tends to draw from 1930-55 (give and take some bits) and thus, no infantry weapon was around during that time which could be useful in an AA role: and towed AA guns are cheap.
Monitors: Mostly used for river fighting, and given naval combat in WW2 was between Subs/Battleships and carriers, these units would be ignored completely.
Heavy Cruisers: At this moment, I feel like lvl 4 cruisers can carry this title ATM, but I would like to see them within their own tech branch one day.
Government
I also think you aren't really aware of what a 'left' government is, you do understand that the Soviet Union was a left government? And they had insane production- as did the US, and that was more right leaning. I would like to see a Government type in this game, but due to the spectrum of Left-to-Right, we'd be here all day. And changing the flag/name of the country as you change the government? Just seems complicated
Unit starting World Map
Buddy, the idea of nation 'tiers' would mean people would join, find out they can't play as a decent nation, and then leave. Japan, UK, Germany, Communist Russia- all these would have to be tier one, and most of Europe and the Northern Americas. People would just go inactive and stop playing.
And as I've just found out in another thread, people don't want a 10 player version of the World Map. And Unique units also seems off, as Germany would be the most powerful tank nation, the Soviets would have insane Arty, the US/UK/Japan would be unstoppable at sea, France would have the ONLY super heavy tank in the world, Italy would be laughable (all their equipment was dreadful) UK fighters would be a step above the US, as the Brits made the first Allied Jet fighter and the Germans would be a step above them.
I see what you're going after, but it just doesn't work out. People would rush to get certain nations, and then leave. People leave in the current Blitzkrieg 1939 map when they have to play as Yugoslavia anyway, you'd have half empty games.
Breakdown
Seriously man, I like your idea's, but this forum is brutal: people here are well versed in WW2 history and will look 'AA Infantry' and be confused, as no such thing has ever taken to the field. I don't play the 100 player map enough to comment on those aspects of your plan, so I'll live that to another member. But you've got a decent mindset and put forward good Idea's.
I Hope you stick around on the forums!