fixed:  "So it really doesn't matter if you need a "60%" JCM to fix a "40%" joint, or if you need a "10%" JCM to fix an "90%" weightmapped joint."

it certainly matters if you are the content creator making them.  it also matters if you are the clothing creator that has to duplicate them all in clothing as opposed to just transfering the weight maps from the base figure.  even if you are willing to put in the time, its still time you could have better spent making more content.

"Not to mention that a conventionally fixed rig is backwards compatible to Poser 7. (And perhaps even further)."

yes, that is a very valid point - and why there will always be room for products that make use of all of the new features, and those that cater to all legacy versions of Poser.