If shooting and looting don't scratch your co-op action RPG itch, then maybe taking down criminals in Gotham City will. Gotham Knights is basically what you get when Batman is nowhere to be found and crime runs amok in DC's darkest city. Batgirl, Knightwing, Robin, and Red Hood are filling in for him, and from the looks of it, their plates are full.
However, despite having four playable characters to choose from, Gotham Knights only allows for two-player co-op, as seen in the first gameplay reveal for the game. That being said, a co-op game set in DC's famous city should still be an experience that you won't want to miss out on, and like Outriders, it's drop-in/drop-out, allowing players to team up anywhere, anytime.