This has mostly fixed the drain issues for me. I never use the case, and the AirPods are primarily used in my office during the day connected to my Mac. Previously the headphones would be nearly or completely drained most mornings if I left them in bluetooth range of the Mac.
I'm now through day 3 of use on one charge leaving them unplugged next to the Mac every night. Still drains a bit (5%) or so overnight, but this is much more manageable.
Also the on/off head detection is working reliably on the Mac now.
I would like to see the auto-switching extend better to the Mac where I do not have to click on the Connect prompt quite so frequently after taking them off, then interacting with a nearby iOS device. If I have them on and am using my Mac, they should just connect.