Games often make the mistake of constantly dumping new objectives and toys on you at all times. Open-world games in particular tend to load up your screen with side-missions and things to do. As a result, I find myself perpetually focused on whatever my current objective is, and rarely pausing to enjoy my surroundings.
In some cases I'm sure that's intentional. Games like Infamous or Just Cause 2 are kinda boring outside of the gameplay. The pedestrians aren't saying or doing anything interesting, there's not much to take in. But then you have games like Sleeping Dogs which does actually have a great take on a new environment (Hong Kong), good atmosphere, pretty visuals, and a decent number of interesting little bits for you to come across. But you really have to step back from whatever mission you're on to enjoy all that.
Anyway, Rockstar is an exceptional developer. GTA IV was an amazing experience at its release, and GTA V will clearly be the same.
I would love to do this but I would also want to hear the radio stations too. Maybe they will implement some sort of radio feature to the smart phone so you can listen to music while you are not in a vehicle. If that was in the game I'd walk from one end of the map to the other. Just wandering the earth, like Kane from Kung Fu.
There's a dude in the bushes--HE'S GOT A GUN, what's he doin? I don't know I don't know, RED TEAM GO RED TEAM GO!
^ That's always seemed like an obvious feature for GTA to have, but oddly enough it still hasn't been introduced. Recent previews tell us the in-game phone in V has a bunch of different "apps", but so far "radio" hasn't been announced as one of them.
But the game is supposed to have a legit musical score for when the radio isn't playing. Should be a lot of nice ambient music like RDR has.