With it sounding like all of the threads will only be used for errata, i'm bummed by that as I'm not confident that the majority of Ars players ever look at errata, I have a suggestion for a different product.
Presuming no new version of a 5th edition core rulebook with fixes, how about a new official release of a grimoire? Just spells to help make it more clear how the magic creation system works? Even if it was pdf only, I know I would love that. I know there are online resources for spells, but I personally would rather pay Atlas for official spells, even if some of those spells are from other products, to make things easier to find!