Wellll... I don't know to be honest. The PG-13 superheroes like Avengers (ie. most of the MCU) have started tiring me out. DC is still lagging 10 years behind. Interest in the X-Men franchise films seems to have petered out. The novelty factor is gone. We've gotten used to seeing comic-accurate costumes, specific plot points straight from classic storylines, multi-hero teamups, complex world building across multiple franchises etc. It's no longer impressive.
I think the land of R-rated superhero films is still rather unexplored. Deadpool and Logan have both heralded that, and have proven they can be economically viable. I think the next step could be studios embracing that, and starting to make films about superheroes that need the R-rating to be appropriately faithful to the characters. Like Deadpool and Wolverine, unsurprisingly enough. It's just that the array of characters like that are much slimmer, and have already been covered in either earlier films (like Punisher) or the Marvel Netflix lineup.
Another step, which I hope filmmakers would realize, would be trying to escape the term "superhero movie" altogether. Regardless of film, there's elements that are present: you need the costume, you need the powers, you need an iconic villain, you need a big showdown at the end. That kind of pattern repetition will serve for a while, but gets repetitive eventually (cough MCU cough). I'd much rather see filmmakers start making genre films with superheroes in them. The Dark Knight and Logan are the best examples: the former is a mob/terrorist/crime thriller with Batman and Joker in it, the other is a road trip drama with Wolverine and Xavier in it. The Marvel Netflix series have done this, but it's yet to arrive on the silver screen. Just think of everything you could do! You could do straight up horror films with Batman. Superman and Green Lantern are perfect for cosmic fantasy. Wonder Woman for swords and sandals.
And of course, at the end of all this, at the point which the superhero genre becomes a parody of itself, a walking corpse of a franchise, it's time for the ultimate: Marvel Zombies. Just throw in Superman and Batman there too.