I agree that it can easily become opinion-heavy, but choosing the right measurement criteria can keep it a bit more objective.
Most of the headings in the
Retroblast Joystick Roundup seem like a good starting point -- individual stick writetups
here.
* Degrees to Engage
* Maximum Travel (Degrees)
* Range of Diagonals (Degrees)
* Pressure to Engage
* Sound (1=Noisy, 5=Silent)
* Install (1=Hard, 5=Easy)
* Rotation (1=Hard, 5=Easy)
* Diagonals (1=Hard, 5=Easy)
* Stick Height (inches)
* Stick Diameter (inches)
* Install Footprint (inches)
* Unique Features
* Cost
IIRC Kowal doesn't care much for the Retroblast stick reviews -- perhaps some of the extensive reviews he has done
here could be compiled and translated (some writeups are only in Polish) into a similar chart.

Scott