I'd like to see something specifically about managing the low end in a mix, how to measure it and control it, especially as we are mostly mixing in less than ideal rooms.
How to get the thump without the boom, how to get it to sit evenly throughout the mix, how to monitor it (analysers, reference tracks,etc) how to make it work across all common listening environments (iPods, low budget hifi, high end hifi, in car, kitchen radio. Is there a safe middle ground? that kind of thing.
This could extend then into Mids and highs in further lessons.