4) Arranged teams have an inherent advantage over non-arranged teams. This is true in any game IMO. The availability of voice chat makes talking with your mates so much easier than having to take the time to text in game. There is only so much that any studio can do to make things easier for randomly assigned teams.
4a) Having separate arranged and random cues is a bad idea unless there is a huge surge in active players in team games. Even with these relatively healthy numbers (I remember the dark days when the peak players was at around 2,000) a separate cue would make wait times extremely long.
5) Balancing the game around the arguably poor faction design of the USF/OKW/UKF was difficult. The factions had unique mechanics but often lacked non-doctrinal tools to deal with all situations one would find in automatch. One effect of the balance patches, community-run or not, was to eliminate some of the unique features of each faction. For example, USF howitzer and M8 Scott no longer fire directly, instead always fire in an arc; OKW mechanized truck no longer makes you prioritize between munition and fuel gain; OKW veterancy levels are toned down so it takes them longer to unlock all abilities and bonuses than before.
Arranged team always favored Allied over Axis since Allied factions have more gaps covered by strong alternatives. this lead in arranged teams tournament being always won by who was better with Allied factions. The balance team aimed to change that, they said it themselves couple of time.
I'm not complaining here (I posted on the lobby, not balance) I just state that the balance team didn't balance more the game than it was, they adapted it to their view but not balance.
But you're also mixing two different things in your examples PakH/Scott have been nerf out of the blue with because they were too strong but nothing has been made to fill the gap they were supposed to cover, Vet5 OKW has been nerf as a compensation for the gaps filled over time. OKW is the faction that recover from the many design gaps it has originally to the point where people started calling it Ostheer 2.0
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The "Relic didn't allowed us to move unit to stock" look more like a meme today. We all knew it since the begining, MrSmith already mentioned it when he started to propose changes back then. So still using it as an excuse 2 years later isn't valid anymore.