I once listened to a dnd podcast where they played a very truncated version of Curse of Strahd for 5e, and at one point they party was granted a wish for some reason and wished that vampires were good (among some other zany body switching wishes or something). Anyway, it pretty much ended the adventure immediately and it made for fun radio.

But I was just thinking, what if by some twist of the cosmos, someone, maybe the mad mage in the mountains, managed to change Strahd's alignment. Instead of the antagonist within the realm of dread, Strahd brought you there to help clean up the place. He is still a prisoner, forever trapped and tormented by the fates, but at least he could be a benevolent ruler and try and old back the evil forces in the land that corrupt all that live there. Perhaps some intrepid adventurers could even make secure the Amber Temple. Or maybe deep down, Strahd knows that stirring things up will eventually cause the forces of evil to return him to an evil state.

I am currently running CoS, and doubt I will ever bring a game like this to fruition, but thought it was a fun idea to launch out into the Astra Sea.

Post the game, many would sign up.

I don't see any reason why it wouldn't work. You'd have to pick a new villain, and probably have it be one that Strahd is not capable of taking on himself, and I think that would be the only major challenge you would have to deal with.

Oh, when I said I am running CoS, I meant in the traditional sense.

I was thinking about that. I think there are a few options that can be used by themselves or together to keep Strahd occupied/away.

Logistical: It requires effort to make good laws and execute justice. On top of that, the denizens of Barovia have been trained to take what they can by corrupting others, and there are very few executors and stewards Strahd can rely on.

Former Allies: There are a number of former allies that, although not as powerful in and of themselves as Strahd, together they can be dangerous. Both Baba Lysaga nad her Hut are both CR 11. Rahadin and Madam are both CR 10, and there is this bit, "The Dark Powers of Ravenloft would consider Madam Eva a worthy choice to replace Strahd as the master of Ravenloft". Also, rogue vampire spawn- good, neutral, and evil.

Former Enemies: There is no reason to believe that Strahd's former enemies would forgive him after a change of heart. Rather, they would probably see it as an opportunity to destroy him.

The Dark Powers: The very forces that turned Strahd into a vampire are still out there, beckoning and condemning him.

Everyday temptation: Strahd knows the depths of his own depravity and how easy it would be to just take what he wants and rule over the Realm of Dread.

Azalin Rex: The undead Wizard King is a powerful nemesis of Strahd who, I believe, has attacked Barovia in the past. He may want to take over as the Lord of the Realm of Dread.

The Mists: The Mists themselves may preclude Strahd from venturing from his Castle. All of Strahd's time may be dedicated to freeing the demi-plane from the strangling mists, and it's very exile from its native plane.

I think I am too busy with my other games to run one like this, but I would play in it, haha. Could be a good option for players that are familiar with the campaign and want to play it from a different angle, since Strahd would give the adventurers information about the place anyway. It would be more of a heroic adventure of the characters kicking butt. Less Lovecraft and more Robert E. Howard.

I'd be interested in playing in it.

I always found Strahd to be a tragic character rather than evil. Until now my players always managed to redeem him somehow.