Well, I don't particularly mind who I play or how many for that matter other than the characters that I already have, I just hate when it's just "let's whack in whichever character is supposed to be in the scene and just keep going till I decide to stop" because there's literally no structure. 

I pretty much always just play whoever the other person doesn't feel like playing as really

I'll work on a response in a minute, I'm going to have to go eat soon