The elephant in the room in all this is that Wikinews lacks the critical mass of editors to overcome these issues.
So...
you could have a strict review system; if there were enough good reviewers you could cover a broad spectrum of news; if there were enough editors you could implement collaborative & freely edited original content; if there was enough interested editors
The problem is that Wikinews already has a high barrier to entry - it doesn't fit a model of casual contribution once or twice a week (or month).
Producing a functional daily news outlet (website) requires a substantial full time staff... of course so does an encyclopaedia, but an encyclopaedia doesn't have a weekly time limit on story completion... so we can adopt a more leisurely model.
For "news" that model does not simply cut-n-paste across.
Tom