Interesting piece of software and concept.
Unfortunately I don't have a printer to be used as testprinter and I don't
like to tinker with my production printers so this is just my thoughts
about klipper.
Comparing the list of supported G-codes with my latest prints sliced using
Simplify3D only two G-codes fall out.
The first was M84-Disable steppers and that is easily fixed because M18 is
an alternative. (alias code like G0 and G1)
The other code that I found missing was G29. I have seen that some
experimental code is supplied as alternative but for me the G29 command is
an essential code because sometimes I print on clean glass and other prints
is on blue tape. I use a BL-touch probe.
So a before G29 is implemented I don't think I will change to klipper.
Have fun
Niels