Mario 64 is a bit of a worst case as the game was being developed at the same time as the hardware and had to get out on day one no matter what. Between the Japanese and US releases I believe they even fixed some bugs.
Some of the things he did seem quite obvious, like cutting down the repeated calculations for every single coin on the screen. You have to think they would’ve thought of that if they have the time.
It would be interesting to see a series like this on a number of games over the console’s lifetime. Especially if it highlighted the tips and tricks the developers started to learn to get more out of the hardware over time.