Agreed RW. Unless I mistake past case/procedure specifics, it is firmly on the books that Goodell has a distinct limit on his power to decide punishment. So I have been optimistic on Brady prevailing on reduction of the punishment. However that optimism is lesser now because new, and sanctioned, punishment authority verbiage is in place, and because Goodell is blatantly using Brady/deflategate to launch a Barbarossa level offensive to define greater power and authority. Their looking to blaze a new legal/procedural proof trail that allows him to hand out punishment much more arbitrarily. Unfortunately, I assume, Goodell's legal team is good enough to possibly make that happen(hopefully their offensive will be as epic a failure as Barbarossa was).
On the NFLPA request, that's a non starter. The NFL isn't going to give up a scintilla of power without a brawl. I think it is a non starter to look for any amendment to the existing agreement. This kind of change will only happen when the CBA expires/the next negotiation begins, and the NFLPA demands/holds out for that blatant and obvious need for a neutral third party arbitration requirement for all suspension level punishments.