Good post, and I agree with you up to a certain point, and think you only missed one thing. I do not really see the downside of systems as they can ignored for historical / scenario play when that may be called for, am I missing the point?
In point of fact, the balancing of units is a separate issue that would arise when a system is not granular enough for the number of units in a game. My favorite systems are multi-factored with eras of availability / force organizations / incompatibilities / type caps that also must be accounted for when putting a force together, but that is beside the point.
I read, and reread, and then searched the topic before hitting my breaking point, where were the puns?