From being on (and moderating) other boards, these are a few things that we have received as suggestions. They might not all apply here but they are suggestions.
1 - Have a Quick Reply box at the bottom of a thread so people don't have to go right into the reply screen to post.
2 - Have an icon that shows if you have responded to a post or not.
3 - Have the ability to change fonts in posts (colours, sizes, bold, italics, etc)
4 - This is something that I actually noticed here but I often get stopped by the 60 seconds between posts rule. Is there a way to change that to a shorter time limit or make it a character limit instead (like 5 character minimum or something). I tend to flip quickly through posts and reply and have often gotten that error having to wait and refresh for my post to go through.
That was just a few things I have seen. Not sure if any of them are possible here or not.