I agree that helper functions to tune in some properties of the printer itself, filament etc, would be helpful.
@dmbutyugin already started out on such a journey here Extruder PA synchronization with input shaping - #2 by dmbutyugin and I find it extremely useful.
Still I believe this should rather go into Moonraker, e.g. as some sort of calibration plugin that generates appropriate gcode and executes it instead of overloading the “firmware aspect”.
In any case generating tuning gcodes and helpers is a different story to implementing a filament database into Klipper.