6. Vehicles
Not just a few vehicles, but the most vehicles any GTA game has ever had
to date. Remember the jetpack from San Andreas? How about the Hydra? It'll be interesting to see what new vehicles Rockstar introduces. We've already seen a taste of what's to come from both trailers, but there are bound to be a lot more. In San Andreas, I personally enjoyed driving a golf caddy on the sidewalks yelling "get off the road!" There will be submarines and a fully explorable ocean. It's not clear if the submarine will only be used for a single mission, but the addition of scuba diving hints that you'll be able to access it whenever you wish. Let's hope there are more 'weird' vehicles this time around (like the hovercraft in San Andreas).