6) Copycat
We’ve technically already met Copycat, but seeing as Morena Baccarin’s Vanessa Carlysle didn’t display any of her comic book counterpart’s mutant abilities in Deadpool, it’s essential that we get to see those in the follow-up.
A good way to explain the sudden onset of her mutant powers would be to reveal that Ajax performed some of his dastardly experiments on her before Wade stopped him, though it could just as easily be revealed that “Vanessa” is just the current form that this shape shifter has taken in a bid to live a normal life.
What separates her from Mystique is that Copycat has the ability to imitate the powers of any mutant she comes across, something which obviously makes her extremely powerful. It would also shake up the relationship between Deadpool and Vanessa in a major way, something which might be pretty important, especially as it would obviously be quite redundant to have her fill the role of damsel in distress for a second time.