A lot of this I could actually envision taking place in the game, even things like speeding and drug use. With appropriate execution they could bring a lot of value to the gameplay experience.
E3 demo, that was the fly swatter to the fly. Not Rockstar's style with GTA, too grand an experience.
And the one protagonist vs multiple? The first trailer featured that CJ-esque character way too much to be a coincidence. Or Rockstar is really fucking with our heads. I could kind of see that.