Rothgar originally had the idea for the wiki when thinking about updating the outdated UIbuilder documentation so that's definitely something which should go onto the wiki, basically all object types and their properties as well as all UIscript methods. Rothgar said (a year ago) that he'd help fill that out,we'd just need to get started on it.
Apart from the reference section I think a FAQ/tutorial section and finally some modding examples.
I agree though, it's a bit overwhelming to start with a blank page.
