Wow!!
You really layed it down on this one. I like all your points, and I'm sure many would consider some of them controversial, but all have a rationale behind it.
Your opening lines about class size made me think of the magic I have seen Filipino and Nigerian teachers in Cambodia perform, commanding 100+ kids through various activities without the aid of a megaphone. Definitely more quality in smaller groups, but sometimes the system provides irreversible constraints.
Yes, there were a few that suprised us, but the neuroscience backed it up! Funny how myths start and persist.
Yes, big classes are often a must in countries with limited resources. Repetition and activities to cement learning are so important - how deep the learning goes depends on so many factors, such as the student's attention, study habits, home life and so on.
I feel sorry for teachers teaching to such class sizes, but then again, they have an excuse not to give individual attention!