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I want to say that part of the reason there's no need for more blog content etc. is that you have made excellent improvements of late. Making it so easy to add letters, and then also having the editors come in and *rate* the letters, so that if you are in a hurry you can just read the editor's choices, that's brilliant.
The only of your new ideas that might be useful is making it easier to link to or upload non-text media, but I think it should be kept in the context of (public) letters to the editors or journalists. Then the editors and journalists can decide whether to follow the leads up with full stories, just like editors and journalists always have.