Lot's of stuff
This is a spot on analysis. Great explanation on the difference between teamgames and 1v1 and why the scaling will never work without changes.
Unfortunately I have to disagree on you solution. Not because it wouldn't balance team games but because it would require far too much work and would leave the games in a far less enjoyable state.
To balance the maps for team games like they are in 1v1s you would have to essentially scrunch all the maps down so that the time to arrive in the battle is similar, and then spread out the map large enough for more flanking and harrasing to take place, essentially spliting up the players. All you will left with is a long but shallow looking map with every fighting their own 1v1s and slightly interacting with their neighbors. And that doesn't leave much room for variety in maps.
Besides I don't think there is anything wrong with the 4v4 meta and maps. I think it's perfectly fine as is and both sides are able to succeed depending on teamwork and skill. That is until the late game hits and the axis side get's a variety of extremely powerful weapons that are easy to support with extremely effective support units and maintain even while taking losses, while the allied side either has to depend on doctrines to compete or simply unperformed compared to their opponents.
The problem is in the late game, there is no need to change how 4v4 works in general. That's why I have been such an advocate for fuel upkeep. Which would help keep the resources flowing around in the late game under a much more controllable state.