There’s always a discussion surrounding how villains are treated in any comic book cinematic franchise. Most commonly, they survive for mostly one film and those that make it out alive aren’t around for too long. So, while the heroes continue to get some development, outside of Loki, most villains end up one-dimensional due to the lack of screen time.
As it turns out, Crossbones actor Frank Grillo feels the same. His character was seemingly set up for a long future with the Marvel Cinematic Universe but faced an untimely end during Captain America: Civil War. One might argue that without his character, the events of that entire film wouldn’t have taken place but it seems Grillo wasn’t a fan of how his character was treated, and seemingly confirms he’ll appear in an upcoming DC project.
They never told a story [about Crossbones]. The mythology of the MCU and just what Marvel has in its pool of characters, it’s so deep. Crossbones was there for a minute, but he was supposed to be there longer, then they went the direction they did. I think Crossbones serves a purpose, but I think the interesting thing is that if you see how many people around the world have responded to Crossbones, and again, he’s on the screen for a very f–king short amount of time, I think there’s more there. I think there was more meat on the bone. I was disappointed, which is why I went over to DC.Frank Grillo
It’s certainly a bit strange as he probably had more screen time than any villain in the MCU. Plus, he also returned for two projects even after his character died, as he returned in Avengers: Endgame and even voiced Crossbones again in What If…?. So, he wasn’t a character that was completely sidelined and it would’ve been great to see him return especially with future multiversal storylines. But going by his comments, that ship has sailed.