I think I heard about that. Nice.
As for Dark Raiden, I hope he's not too much of the focus on the antagonist side. Should be Onaga imo whose return is long overdue. Plus the idea of Dark Raiden to my understanding is that he isn't really evil, so much as he is an edgelord who protects Earthrealm through ruthless means by needlessly killing/destroying things. I don't know, but I never liked the concept that much and prefer the normal uncorrupted Raiden, even if he isn't perfect and makes plenty mistakes in the story.
Raiden has never been boss-like either, so having him as like a final boss would be a bit underwhelming, but I expect that may be what we end up getting. Will have to see.