I think that is a great idea. There are ideas and short discussions strewn around threads here and there just to (seemingly, maybe they aren't) be forgotten when the thread eventually dies (there was for instance a thread for which applications people want ported to fremantle, which I can't find now). Particularly with someone collecting the ideas in the first post (thanks, zerojay!) this is a good way to collect them. I am not sure why stickies aren't popular here (granted they are sort of in the way) but maybe these sort of threads might be suitable as such?

Another point, if I may. I am not sure if I can speak for all newbies, but for me the brainstorm system is a bit scary. It is up for public scrutiny by all these experienced guys and If I had an idea I would feel I had to think it through very carefully before posting it there. Also, I may have ideas but not the technical know-how to know if they are doable or the background to know if similar solutions already exist. Thread discussions are a bit less scary to throw ideas into even if they are not reasonable...

EDIT: added italicized parts