@ftxcommando I tried ctrl+shift in loki! Kindof annoyed me that the buildings didn't show their mass value!
Regarding the other things though - my point is simply that at the lowest level, players are focusing on a basic build order, and while an enemy figuring out a clever cliff-build on a mapgen map feels like 'wow, I got outplayed', having them do it on a pre-generated map feels more like 'I lost because I don't know maps yet'... And then after learning that lesson you have to figure out how this affects the build order that you're already struggling to get right, next time you get that map!
While low-rating players playing mapgen maps would see it as an opportunity to practice that build order without any 'funny stuff' messing it up!
I'm certainly not against pre-generated maps in low-rating 1v1 though! They're great, and teach good lessons... I just think mapgen might not be excluded in principle; if anything it feels more 'fair' to newbies, and can still present lessons while feeling that way.