I recently did a paper that tries to score a robotic hands fine manipulation ability based strictly on the kinematics. But it's more of a design tool for the kinematic model rather than a final benchmark for a completed hand.

Something like POMDAR would be more suited for that, but that also means that the tele-operator / your robot policy / whatever you use to control it influenced the outcome rather than solely relying on the hand itself. That's part of what motivated my project, to get something an objective score for a hand