Yeah I think there’s some good ideas that have been built up with the ABL devices over the years, and that mesh leveling seems great. However I also feel like more people should take the time to get their beds physically as flat as possible first, because otherwise your printer spends a lot of time micro-stepping the Z, and I’ve seen some mesh maps that looked absolutely horrible.

Playing around with arduino devices, I have some laser rangefinders that seem like they could work well for an ABL. That might also be a good way to map out the idea I mentioned about creating a thin full-bed shim to get a truly flat bed, and after that perhaps you would only need to do a fast four-corner calibration with the ABL to make sure nothing has changed.