I want native support (with hotswapping) for languages like markdown and textile, somewhat like AJ Fork (which from what I can read in the developers blog obviously just stopped being developed sometime without letting the many users know). There are several people asking for help on how to add this to cutenews, but neither of the threads I found here can explain how to. If I knew more about php I'd start dissecting AJ, but since I'm blank I'd rather not.
To me this is the most important extension, together with perhaps friendly filenames and the extended date/time-addon, all of which I think should be vanilla from CuteNews.