I think there should be some type of skill learning in the game like with all the book you see around. Medical book so when you have that book on you, you can skill up your medical skills and so you give blood faster and so on and then you could have mechanical book so you skill up on mechanical skill and can fix cars faster and maybe building skills, cooking skills,and so on that way you can go lonewolf and skill your player up or team up and you could be specialized in a skill