I hope I'm wrong but I don't think the Motu Proprio is really coming. At least not in the way many of us are hoping for. We may get a universal indult BUT I suspect it won't have any strength. The bishops will either ignore it outright or the Vatican will give them a face saving loophole of some sort so they can ignore it politely. The other possibility is that the Tridentine Mass will be changed to suit non Catholics and Romanized Protestants. (Catholics in name only). The faithful will be told to accept this new version of the Tridentine or take a hike-- driving the hard core Traditionalists even further away.
At any rate, don't assume that the Motu Proprio will be the great fix to the Church's problems. It's been bad for decades and it's not going to change overnight barring a miracle.