FWIW, comment editing finally came in after a lot of pressure on J, but was largely in response to my suggestion of broadly what happened, however in comments this was covered (By Azz, as it happens) here

azurelunatic (from 68.227.245.34)

January 9 2007, 07:27:27 UTC
Regarding abuse of the comments: if a comment was screened to start with, then unscreened, an edit would re-screen it.

matgb (from 193.69.116.84)

January 9 2007, 07:32:13 UTC

Good catch. I rarely if ever feel the need to screen comments so covering them didn't occur to me.

azurelunatic (from 68.227.245.34)

January 9 2007, 07:41:55 UTC

I have a community with non-member posting screened, to avoid dogpile flamewars.

I don't know why it wasn't implemented originally, I'm guessing coding time rather than desirbability but might be wrong, and think it's almost certainly a good idea,with a proviso that some way of making it unnecessary for minor edits, maybe involving trusted friends or something?

I'd hate to have to re unscreen someone who makes a bunch of typoes, fixes them, then sees they've put a comma in the wrong place.