This was an interesting overview. Thank you.

A minor correction: both the original Cheetah and Mini Cheetah motor designs were QDDs and were using BLDCs. The innovation was from using a off-the-shelf BLDC model as much as possible instead of a custom-design/modify one. Moreover the placement of electronics and gearbox was much more compact, leading to the modern day design. If any thing, the original Cheetah motors were actually simpler than those in Mini Cheetah.