CRAN,
IMHO. Yes & No
For the pleasure of a theoretical discussion;-
I believe that all, or most, teetering rotors have a fixed pre-cone angle in their hubs. This pre-cone angle is around 2-3 degrees, and is probably close to the dynamic coning angle of the rotor disk, when hovering at gross weight. Variations in rotor loading will, of course, increase or decrease the actual dynamic coning angle above and below that of the pre-cone angle.
I agree that additional vibration &/or cross-coupling activity may take place when a blade's centers of lift, percussion, drag, and mass etc. are not inline with the feathering bearing axis. It must be remembered though, that even if a blade's 'centers' are aligned with the feathering axis, there will always be misalignments between the 'centers' of the two blades and the teetering hinge.
I have felt that if Robinson wanted the two outside hinges to be only coning hinges, and to not be subjected to independent blade flapping, he should have mechanically linked the two hinges together, so that they rotated in unison.
Again IMHO, the advantage that you mention may very well be true, but I suspect that the 'sloppiness' of hub, due to the three hinges, MAY be the source of other difficulties.