I'll just mention a few.
New secrets. That would be really great, Tom. And make them good. None of this *********** stuff (censored because I cannot discuss secrets on the BBS).
New levels would be cool, that or an added way to get experience. I'm not too worried about that one though.
Finish Pico 2; it seems that a lot of people are waiting for its release.
Spice up the Audio Portal somehow. Even allowing audio reviews to be counted towards peoples' overall reviews could work, because more people would listen to the music in the Audio Portal and review.
Allow blammed flashes' reviews to be flagged as abusive. Even blammed authors have feelings, and abusive reviews in general should not be left alone, for some people write really stupid reviews if they know the flash is going to be blammed.
Make the BBS even slicker than it is now. I don't know how to do that exactly, but you have done it before (it looks different compared to 2 years ago).
Update profiles. This could be from changing the background of profiles (a black profile isn't the greatest looking; perhaps matching it with the BBS theme) to allowing users to record their favorite audio artists and songs. Maybe even more slick images for ranks in both level and blam/protect points (3D perhaps).
I know that I will have some spelling errors, and some of my writing will not make any sense. This is because I got some oil in my eyes, and they are watering. Also, I'm quite sure that I will come up with even more ideas some time later, but I could just post again if I do. Thanks for asking for peoples' suggestions!