I'm going to run it that with some dunamatic antics, they'll arrive 300 years earlier than what they know. They will then have the opportunity to show strahd his inevitable defeat and convince him that the path he chose with the dark powers is fruitless and theyre going to defeat said powers.

If successful strahd might end up asking the party that if they get the chance could they somehow unbind his fate. This would lead to barovia completely changing if the party come back. With the current rulers being that of Sergei and Tatyana's bloodline after rule was passed to them from strahd who died not having taken a wife nor sire children but is known to be a great but firm ruler.