One, any Fediverse server software would have to be capable of altering comments from any Fediverse software. Don't think that posts, comments etc. aren't formatted the same everywhere. They aren't.
For example, Mastodon would have to know and understand that it would have to remove
@osma@mas.to
from Misskey, Sharkey, CherryPick, Iceshrimp etc. notes, @[url=https://mas.to/users/osma]Osma A 
[/url]
from Friendica, Hubzilla, (streams) and Forte comments and an invisible shadow mention from (streams) and Forte comments, too.Two, anyone in the Fediverse would have to always have full and unlimited permission to alter everyone else's content without their consent. This is particularly crucial in the cases of Hubzilla, (streams) and Forte with their highly advanced and fine-grained permissions systems that don't even cover having your content altered by others.
Three, edits on any Fediverse software must always be federated to absolutely everywhere and anywhere in the Fediverse, no exceptions, regardless of software. AFAIK, there is Fediverse server software that still doesn't understand edits at all, and that will either ignore received edits or understand them as and treat them like new posts.
It's very similar to the wish for being able to edit alt-texts into other people's posts which seems to pretty much always come from people who think that the Fediverse is only Mastodon, or at least that everything in the Fediverse is like Mastodon plus one or two extra features.
And let's be honest: If you give especially Mastodon users the ability to alter other people's posts, they will want to alter other people's posts in lots of other ways. Like, delete summaries on Friendica/Hubzilla/(streams)/Forte posts because they're "abuse of the CW field" from a "Fediverse = Mastodon" point of view. Remove all hashtags but four, regardless of these hashtags triggering the automated, individual, reader-side content warnings that have existed in the Friendica family since five and a half years before Mastodon was first published. Cutting "long posts" (= everything over 500 characters) down to a maximum of 500 characters because "the Fediverse was invented by Eugen Rochko for only microblogging". Even removing any and all mentions of the Fediverse beyond Mastodon. Removing text formatting because "it has no place in a Twitter alternative". Or removing all contents from posts or comments altogether.
Of course, the very same Mastodon users will completely flip their shit if a Friendica user comes and copies their 20-post threads into one long post, deletes the contents of the 19 follow-ups afterwards and replaces the content warning in the abstract field (= their CW field) with an actual abstract, just to fit it into a Fediverse culture that's way older than Mastodon itself.
#Long #LongPost #CWLong #CWLongPost #FediMeta #FediverseMeta #CWFediMeta #CWFediverseMeta #Fediverse #Mastodon #NotOnlyMastodon #FediverseIsNotMastodon #MastodonIsNotTheFediverse #Misskey #Sharkey #CherryPick #Iceshrimp #Friendica #Hubzilla #Streams #(streams) #Forte #Mention #Mentions #MentionTag #AltText #AltTextMeta #CWAltTextMeta #Permission #Permissions