I may indeed have it backwards, but let me explain my reasoning and let you (and hopefully others) tell me where I am wrong.
My understanding is that while this sloppy, illegal fix is indeed bad for most of us, it will not mean that nobody gets relief. I have been under the belief that pre-SORNA registrants will still be reverting to their original sentences. So if you had a 10 year registration requirement and that got boosted to 25 or life, that you would go back to 10, even with the fix. I have believed that their urgency to get this fix through is not to prevent that, but rather to curb the 10,000+ who they would have to give relief to because the previous version of Megan’s Law expired when AWA came into effect.
What that would mean for those whose original sentences would have expired, or for the relatively few like myself who weren’t required to register at all pre-SORNA, is that they would be removed from the registry. Which I’m sure they don’t love, but they are happy to trade the couple thousand who would be removed under those circumstances to make sure that anyone sentenced at any point pre-2012 can’t walk on what they would perceive as a technicality.