Three things I would want next for Radio (I am independent from UserLand but I use Radio as my publishing platform):
- Wiki publishing (Paolo agrees).
- Photo album creation and publishing.
- Modular templates. This would allow me to select a module from a list (a second blogroll, a subscription list, a photo of the day, IM contact info, etc.), configure its use, select the side of the weblog it will appear on (depending on the template), order the module among the selected modules, and publish it.