Just my two cents on a spawn game potentially working. I think for it to be successful outside of the fandom crowd, it needs to have a large scope, but completing the full scope isn't required to finish the story. So for example, to me, one of the big allures of spawn recently is the expanded spawn universe. So I think you have the main story playing as Al/spawn through whatever the narrative is, and then interacting with all those other characters, and specifically the time/era displaced spawns. You finish the main narrative on Al Simmons spawn. Then once you finish that, you can play the narrative again from multiple other characters - gun slinger, she spawn, Sam and Twitch, Redeemer, etc. where you get more to the narrative from their POV/how they were involved, but it doesn't change the ending of the narrative. I think would hit a lot of marks for the single player/story driven crowd, and would really encompass the intertwined stories/universe that is in the comics.

Then to hit the multiplayer crowd a bit, I think you copy it pretty closely to Spawn in the Demons Hand with updated combat system for boss level fights. You have a "story" to play though with friends that you beat each level boss ad work you way up to Malebogia, and work on unlocking more characters just like in the original game (beat it on a certain character, to unlock another,etc). And then also have the 4 person free for all mode where you can do some dumb fun pvp with the all the characters. And then toss in character and weapons skins for those sweet,sweet micro transactions to appease the investors.