So as I sit here rotating between my renditions of Wonder Woman, Catwoman, Zatanna, and other superheroes, I've come to the realization that Volition could potentially do something pretty crazy with SR5. Let's get "Option 1" out of the way first: Reboot. In many ways, there's nowhere to go from here if the Saints are to remain a "gang" in the way we've seen thus far. The Boss has become the POTUS. That's it. The Saints have reached their peak. On top of that, they're fighting aliens. There's nothing left in this version of Saints Row. On top of that, the sense of progression is 100% busted outside of immediate factors like player upgrades. Everything outside of that- clothes, property, cars, weapons, businesses- are all nearly immediately accessible or made irrelevant by the superpowers. SR2 had a great sense of progression, SR3 less so, and SRIV, aside from the powers, is gone. Within 5 hours you're a beast, and the game is set up in a way that all the "flashy" upgrades and city ownership doesn't mean nearly as much as it used to. This sounds like prime reboot material, which I would be fine with if it meant a return to SR2, but...BUT....what if.....
....What if Volition straight up turned Saints Row into a superhero franchise. I'm not finished with the story yet so I don't know where it goes, but here's my idea: These first 4 Saints games are the origin story. Not only for The Boss turning from a common street thug into a hero, but also the Saints becoming The Avengers, and mutants being created in SR3, and aliens being introduced in SRIV. Add to that the superpowers in SRIV which are a ton of fun, more fun than any weapon or vehicle in the series so far, and Saints Row 5 as a traditional superhero narrative writes itself. Instead of rebooting all the characters, you keep the characters and bump all of them up to superhero status in the real world. Set it in a new city, make new activities revolving around supervillains and stopping crime, bring back gangs but power them up like Infamous 2 and give them all a leader like SR2 and SR3, put random crimes in to the game like Spiderman 2, day/night cycle that affects the kinds of crime happening in the city, "World's Greatest" team ups with your crew, more super duels against enemies that can do what you do, parodies oh God the parodies.
Saints Row: The Age of Ultor. You're welcome, Volition.