There are a couple of things I can think of that I would love to see on the forums. For one thing, I tend to use Recent Discussions a lot to see a wide variety of forums at once. However, I wish I could filter said forums to what I was interested in seeing. There are some forums I have no interest in, and another issue is it is really easy to confuse a forum, like an S3 forum vs an S4 forum in that view. A filter would definitely make Recent Discussions better in my opinion.
Another thing I would like to see is the ability to mark threads as read - without having to read through the whole thing/new posts. There are many posts that we make that don't need to be read over and over, such as giveaways etc. Would be lovely to be able to mark them as read and move on.
Just a couple of suggestions.