Single Comment

I acknowledge that the gradient is not that smooth... however, pieces with
4 or 5 stones and not quite equal: a stack of 5 just needs one tempo to
become a queen *and* can give away one stone and still be a rook. I think
that may be more than the value of one unpromoting pawn.

About the knight->bishop step, I agree that there's a larger cost for
such smaller gain, but bishops can travel faster and they only need one
tempo to become a rook. We should not forget that the promoting/demoting
possibilities of each piece adds to its own standard chess value.

If a player shifts stones between two stacks he's giving initiative to
the adversary. If that is used to achieve a closed draw position, I
believe it's ok, if we think it's ok for FIDE Chess.