I think a very awesome change would be to calculate “amount of diff” prior to deciding if an edit requires storage of a real revision or not.
If you changed 5 letters in a post, sure it can be a “grace period” edit with no revision stored. If you deleted 10 paragraphs it should never be considered a “grace period edit” and a revision should be stored.
grace_period_edits_max_chars_changed default to: 30
Any larger changes deserve to be tracked anyway and can be vectors for abuse, so this would be a great change on 2 levels.
It protects end users from “mistake” nuking own post with a ninja edit (cause a revision will be stored)
It protects the community from “bad actors” that abuse ninja edits and starts surfacing them.
Can not think of any downsides really.