I'd ABSOLUTELY say no edits. I think it's part of the ethos of Nostr--and a reminder that Nostr is different--it's about privacy, and freedom of speech. No edits are a part of that-- Just like in real life--once you say something, you don't get to pull it back. Yes, you can apologize but your words are forever. So it is with Nostr. Think before you speak--both IRL and on Nostr.