An updated document would be clearer and easier to understand. Developers wouldn't have to go back and forth between the document and the ERRATA.
It would not have new features. Those happen in the Community Group, or in FEPs, which, again, anyone can join.
If you oppose forming a working group, that means you oppose having an updated document, and it means you want things to be harder for developers, so we have less software and less fediverse.
One person has been spreading the false claim that only W3C member companies could participate in the WG. This is not true.
There were dozens of non-member participants in the original WG that created ActivityPub. I was not a member, even though I was chair, nor were most of the other AP authors.
If we charter another WG, people who want to join will be able to join.