GTA III had the perfect blend of simplicity and originality. The replay value is beyond it's time. I truly believe the reason why GTA V has little replay value is because it's simply TOO VAST (In comparison).
Even people who havn't taken advantage of the money glitch in GTA V don't find themselves replaying it after a week or so. It seems like there is always something lacking with the Online compatibilty. Something as simple as an "Insane Stunt Bonus" lacks the flak that GTA III once had, and still does. I'm playing it now.
The graphics never impressed me as much as the gameplay when it came to sitting down and devoting valuble time to media. What reason do we have to walk into endless alley-ways (GTA V) just to figure out: "Wait this game is not only too big to explore, but there aren't any hidden packages anyway"! It seems like R* challenged themselves to see how much the 360 could handle. As oppose to following things that worked in the past. It's an overwhelming game (GTA V).
When we picked up Vice City for the first time, what was the immediate effect? Maybe it was nostalgia. Maybe it was the voice acting, the music. It could have been a number of things that made us love the game. But it sure wasn't the graphics. We felt like we were playing a game. No matter how we felt about it at the time. When it boils down to it, PLAYING A GAME is what we want to do. We don't want to pop real life into our 360. We want to escape it.
Somewhere along the line Rockstar decided to devote THEIR time in making a game (GTA IV & V) that was the most realistic pastime on the market. The ball was in their court, and they dribbled it to their own liking. Or the publics liking. Either way, there isn't any reason to challenge themselves in making a game the "feels" like real life. It's such a realistic game (GTA V) its actually boring.
Making the game look pristine doesn't always make it a better game.