"Just get your post right the first time in a text editor" - why? What difference does using a text editor make? You can still proof read the thing in the forum posting box before you hit send. The point is that many people don't even see errors until their post is up there on the screen without that flashing cursor distracting them. And it's not just typos or grammatical errors, it's sentences that you feel you could have worded better, points you feel you could have made more succinctly etc. Sometimes it takes a minute or two to see those improvements.
So I agree that it should be fixed. But I would go one better than just reinstating the grace period. I think a far better system (and I've seen it on other forums) is that you can make all the edits you like until either:
- Someone else posts after your post
- Someone replies to (in this case "quotes") your post
The latter makes sense, because it's just bad forum etiquette to go back and edit a post after someone else has quoted it. I would be 100% behind a system whereby you can make all the edits you like until someone quotes you. Of course the forum software might not support that.