These are things that are unfortunately NOT in GTA V, but I personally think would be cool if they were.
1. Choice D, an option where you basically get to kill everyone you kill in options A, B, and C. That would be Michael, Trevor, Devin Weston, Steve Haines, Stretch, and Wei Cheng. Think about it. Although Franklin was obviously pissed off with Devin, the Feds, and Stretch, he did say upon leaving Michael's house to Michael, Trevor, and Lester "Ya know what? Y'all are all assholes!" Upon picking this option, it would probably be Franklin giving Lester a call then Lester probably saying something like "Well ya know what kid? You're all on your own". I can also foresee after this mission, Franklin getting quite a bit of money bit it still being partially split to Michael's family as well.
2. If in Choice B, once Michael either gets dropped or let up then gets go of Franklin, upon falling from the tower, there's a truck filled with pillows. It then drives away and Michael ends up falling into a truck filled with barbed wire. I'm sorry but as much as I like Michael, that would be hilarious AF and there's no denying it!
3. If you got to play as Chop more often, especially in options C and D as well as in the Lamar Down mission. I pretty much consider Chop the "fourth protagonist".
4. If Michael, Trevor, and Lester were to mention the getaway driver from the prologue more often, like they did with Brad Snider.
5. A Random Event that you get to do as either Michael, Franklin, or Trevor in between missions in which the Russian mafia makes a return from GTA IV, only as nameless members whom whichever of the three protagonists you're playing as, kills in order to rescue a Russian woman with dark hair and darkish eyes named Irina (new Random Event character). Upon getting in the car with Michael, Trevor, or Franklin, she thanks them for saving her and requests for whichever one you're playing as to drive her somewhere.
What are some things YOU GUYS would've liked to be in GTA V that are not.