I'm sure that already existed. Unless he intends to expand the diversity into the realm of racism or other types of bigotry or conspiracy beliefs. In my observation, Twitter is extremely permissive in what kind of speech it allows, drawing a line only at abject hate speech, threats or deliberate disinformation. None of that suffers from lack of diversity of viewpoints. Musk is either intending to allow a lot more shit flinging or he's really deluding himself that he can solve this problem. I'd honestly be more optimistic if he was bringing OpenAI in to do moderation.
Right, so the game becomes making your viewpoint as extreme as possible to shift the window of the council in your favour. What could possibly go wrong.
Not all viewpoints are equally valid. Just finding the middle of the viewpoints that exist isn't moderate because you can't just pretend that all sides have equal numbers of extremists and that somehow their views automatically "cancel out".
With the context of Elon saying it, yes. Diverse views where the views are all reasonable is one thing, allowing extremists a platform to misinform and radicalise is not. Elon has made it clear he thinks extremist rhetoric such as Trump's should be allowed.