The initial motivation behind this was:
1) we don't even want the potentially annoying/offensive comments to bug the owner.
2) it should be easy to tell screened posts from non-screened.
However, I've been increasingly hating the showscreened=1 mode and I want to remove it. Justification:
1) it doesn't avoid annoying the owner: they probably still got mailed.
2) we want people to delete or unscreen stuff. things sitting screened and never looked at just wastes disk space.
3) A couple weeks back I changed screened comments to show with a gray bar, instead of the normal blue or light blue. This makes them stand out easily.
4) Eliminates the extra hassle and server load from people having to click "0 comments", then screened comments, before unscreening.
So, unless there are very good arguments for keeping it, I plan to remove it soon.
Thoughts? (either way)