I think people are really over-analyzing this move. I think it's motivated by prestige, not money, nor is free speech the heart of the matter. Twitter is a stagnant company. They have thousands of engineers that in the span of a decade don't seem to produce much at all, nothing visible or memorable anyway. Long-lasting Twitter problems (culture, spam, algorithm issues) never seem addressed. User growth is stagnating…
2) "do a few sweeping changes, and get out. Thereby proving once again that he gets shit done where others can't. " I'm doubtful as a board member he'll have the influence to make material changes. More like a series of publicly visible things.
Twitter doesn't have an 'edit button' because they're incompetent, it's just an odd choice they've made, and I think there are good reasons there. And 'edit button' is not any kind of material change.
3) I'll bet the speech issue is on his radar.
On the whole, I don't see how musk really changes the nature of what Twitter is, it's a mature product.