definitely a speedometer. but while you're at it, you might as well be able to get tickets from cops for speeding, then get one wanted star for obstruction of authority after making your getaway.
FOLLOW THE LAWS OF PHYSICS. when you crash your car a couple times, dont get it set on fire, bang it up a bit, then it either goes dead or die another way... BOOM
better multiplayer system. by that i mean that there should be no certain radius in which Player 2 can stay in without being disconnected. in english: like in SA, when you got too far from the other player, multiplaying is no longer available. instead, for example, in SA, lets say you both wanna go your separate ways. so one guy goes to LV to play some craps, while the other is jumping off of Mt. Chiliad.
a better selection of weapons. in SA, for the weapon tiers 1 and 2, the M4 assault rifle was repeated. and if i remember correctly, in VC, in a tower in Ft. Baxter, there was this awesome heavy weapon, and then again the uzi, which can only be bought or found lying around. you know, diversify the selection of weapons.
and to add to the one above, including "silent" weapons (e.x.: silencers, fiber wires, a syringe filled with a poison of deadly neurotoxin, etc.)
more interactions with peds, environment, etc. you should be able to interact more with peds, like "how's the weather?" interact more with environment: PURE ANNIHILATION. that includes vandalism, like tagging, shattering, etc. [this part is like one of R* other games: Bully. you could pick stuff up, throw at people, and the controls were a whole lot better than those of the GTA series.]
more(a.k.a. better, slightly tougher) missions. let me tell you. most of the VC missions were pretty tough at the beginning, unlike basically all of SA. by "better, slightly tougher," i mean that the first couple of missions start off with getting used to controls, easy stuff for novices, and as the game progresses, the missions' difficulties do too. also, missions like vigilante, ambulance, firefighting... what about rescue teams? let's say theres a cliff, people are stranded on an island, or something like that. go to the designated area, get in the designated blip and/or vehicle, and you're off.
more diverse weather/weather notifications. snow, storms, and (depending on the area) certain natural disasters. (e.x.: Florida, southeastern America-hurricanes, midwest-tornadoes, california, etc.-earthquakes, and so on.) i guess you can add notices of storms or weather from the radio and (possibly) television.
more vehicles. i can't say which ones exactly, but add more old-fashioned, modern, etc. cars, planes (mostly those of the military), military vehicles (camo), boats, and maybe a skateboard(?) or bike to the list.
smarter enemies. such as gangsters, assassins, and whatnot try to walk around, jump over, swim across obstacles to get to you. or, plainly, better AI. lets just say their high point in life is them standing over your dead character's body.
graphics. when you "modify" your car, you should PIMP it out. when you buy clothes, they're not just clothes; they're freakin BLING. like it was said before, dont wait too long to try on clothes, and dont let too much sun get in your eye. ive noticed that most of the games became a bit more darker. and although we can adjust the graphics of the tv set, no one really wants to.
i guess thats it, but i'll try to add some more on.
