If I had the time and resources, I would build a Twitter clone and focus on just getting journalists, editors, reporters, etc on the platform. This is a powerful community that is quite established on Twitter, but I suspect they would be willing to migrate. Maybe something like, Manuscript Wishlist or QueryTracker, but specifically with a Twitter vibe.
If you had your own twitter clone, what rule/process would you use for determining whether someone is a journalist/editor/reporter? Who should get the 'press' credential?
So many people do only editorialism but call themselves journalists. Journalists who do great investigatory pieces are often independent or bounce between publications frequently. Lots of influencers posing at journalists to obtain a veneer of legitimacy. More money than ever influencing the content of what is being written about. Lots of uncredentialed civilians tweeting newsworthy things. Lots of 'news' services writing articles entirely sourced via tweet.
I think the journalism industry is so blurry and chaotic right now, it's hard to know who is worthy of platforming.
I think it's easy to get sidetracked and lose sight of the social aspect of social media, especially in terms of how people think about Twitter. I suspect my first iteration would be an attempt to make it easier for people in the media business to build relationships with eachother -- especially because, as you say, peoples roles in the industry are often quite in flux.
My hope wouldn't be to give people platform, so much as give media people meaningful connections. Who knows, though. I've not thought about it much. I would also leverage other unique advantages I have, in terms of other businesses, to increase the chances of those connections being built.