Becaus hes the only one that writers use healing as a win condition. Hulk gets a way because it's not a focus of his characters its is unlimited strength, deadpool it's used for comedy, creed is literally now and has been a punching bag for logan for years, Laura her healing never has been a win condition and she dosent have a unbreakable skeleton that negates most damage.(she's been taken out by normal bullets multiple times) she the easiest to deal with out of all of them.
Also with newer characters writer tend to notice what fans complained about with older ones and use that to make them more balanced