I love this thread, plenty of great ideas and it’s exactly why I’ve set up my website which is trying to do exactly the same thing - help people share and receive feedback on their app ideas and also to be a place for developers to get some inspiration.
I’d be interested if people are able to have a look (check out my profile for the URL) and to let me know if they think that such a website is a good idea - clearly the amount of posts on this forum indicates that it is a topic people are interested in.