Well, as far as that goes, Cohen's been a minority owner since 2012, and Alderson goes back even further than that, so yeah, not really a huge change.
But the decisive action is certainly a change. Both for the culture of the game and compared to how Cohen has made things difficult for several women who feel they were discriminated against or harassed at his company.
The Cubs actually look worst here - that's where it happened, he's a Theo protege, and Cubs employees knew about it, though it was not reported to anyone in the front office. Not sure the Dbacks or Mets could have reasonably expected to find out about it, barring a full private investigation-type background check, which, given the pace of these hirings, doesn't seem to be standard. Heck, it doesn't even seem like the Phillies bothered looking into Dombrowski's time with the Red Sox (the international violations, and the fact that he got fired so quickly), because he was already buddies with everyone doing the search, and Middleton got on board immediately.