3) Marrow
With the mutant ability to pull bone protrusions from her body, Marrow had the potential to be one of the X-Men’s most kickass warriors, but instead, she’s typically remembered for being one of the grossest, even though Wolverine also suffers from excessive skeletal growth.
It always seemed like the comic book writers who came up with Marrow didn’t put a lot of thought into her creation, other than shouting “sticky-out bones will be cool and icky” in a pitch meeting one day. Many creators have since tried to add depth to the character, but with no luck so far.
However, Negasonic Teenage Warhead barely appeared in the comics at all and this ultimately worked in the character’s favour, as it gave the writers of Deadpool a blank slate to work with.
Marrow could be improved for the sequel in a similar capacity, by developing the dynamic she shares with her X-Force teammate Cable in a way that could transcend her one dimensional depiction in the comics.
Also, the scope for boner jokes is endless here people.