Could be I'm just new here and missing stuff but here's a couple more.
Nesting! Can it be done. Drives me nuts having to view the whole thread when I only want to reply to a single part of it. Plus, my reply get's lost at the end of the thread. This will become very important if you ever get a thread with a ton of postings.
Once the thread is submitted it throws me back to the thread. I'd be happier were it to throw me back to the newsgroup. Chances are I've said my piece at the thread level.
The login bit. If possible, I'd suggest moving the login over to the main screen. Throwing me to a login screen (I don't cookie) is very disconcerting.
Lastly, the Forum Jump. It would be good if that had the capability to take me back to the main forum screen. My reasoning is that I'd like to be able to see what threads had new posts. The box does not provide such information.
Hope this helps.