Agreed, the focus should definitely be on exploration rather than promotion. Although I feel like allowing some level of promotion while still shaping the thing being built would attract more ambitious projects which might help give the platform a better reputation for collaboration-seeking.

Maybe allow a mix of both? Like, people can open a thread starting from a pure problem and throw in some ideas for solutions. Or start with an idea and, as part of it, describe the problem. Let people filter if they only wanna see one type. And of course people can always link threads.