I'd love to be proven wrong, but I feel like another serial killer mystery is exactly what we're going to get, one way or another. It just seems to be the structure that most naturally supports the noir detective genre that Reeves seems pretty determined to work within to separate his take on the franchise.
It just ticks all the boxes of "imminent threat to establish stakes", "Batman and Gordon need to get to the bottom of this to find/understand the killer", "the investigation rabbit hole leads to more revelations about Gotham's history of corruption", etc. I mean Reeves has been more or less signaling that this is what the movie is going to deal with, specifically that last part.
The Batman was probably the darkest take on the franchise we've had yet. I think it would be pretty tricky to walk back the threat and tone Riddler represented to something less deadly or "scary". If we're not following a trail of bodies then there is going to have to be some sort of bigger looming threat. As much as we'd all watch the crap out of one, this isn't going to be a hangout movie with Batman where he's just solving a crime of the week. And I think we can also be reasonably confident that it's also not going to be a 90s superhero where we have to watch the villain's origin story unfold in the first act before the stakes are established. There is likely going to be an opening scene inciting incident that sets the stage for the new threat in Gotham and the plot will follow from there. Again, would love to be wrong and have this movie totally take me off guard. I'm just not sure what other direction even makes sense as a logical followup to The Batman that fits into that world/aesthetic.
