If they were to add fuel consumption, maybe also add maintenance to the vehicle. Tune ups for older beaten up vehicles to help reduce fuel consumption, regular oil changes and possibly new tires? It would also benefit their wallets, more shark cards being purchased for vehicle maintenance. There is a mechanic in gta5 but keep him for damage repairs but the players pay for operating costs. You would have to be more conscious of running from the cops, especially if you jack a car from the hood that's only got "E" nough fuel to get to a gas station. I'm definitely for more realistic more simulation. Gta 6, the last game you'll ever need to scratch every itch, if you stay away from the ladies of the night.