3. Full Character Customisation
Another thing we can thank San Andreas for is the introduction of exercising. Though character customisation was nothing new at that time (Vice City was the first to introduce costumes), San Andreas went further by giving the player further options with the protagonist CJ. Not only could you alter his clothing, but also his hair, physique and even add tattoos to his skin. Unfortunately, those options were never seen again past SA. If GTA V is going to be the biggest entry, it has to include those customisation options and/or more for it's characters.