Add "libinput quirks suggest" as a user-visible tool
$ libinput quirks suggest event18: Synaptics PS/2 Touchpad: should set AttrPressureRange event18: Synaptics PS/2 Touchpad: should set AttrThumbPressureThreshold event19: Some Trackpoint: should set AttrTrackpointMultiplier
Then add this tool to the reporting-bugs page so users can at least pre-determine what's probably needed. This requires some more documentation of what attribute does what.
See e.g. #4 (closed) where this would've been useful.