Having finished GTA 5's story mode twice, I have come to realise what a let down the game is, despite all the hype. First of all, there are only 69 missions, compared to 100 (I think) in GTA San Andreas, which came out way back in 2004. The missions in GTA 5 are at best, mediocre, requiring limited skill to complete. You get awarded either a gold, silver or bronze star, depending on how well you performed in each mission, but for some reason you don't find out the criteria for each star until AFTER you complete it. In contrast, San Andreas missions were often edge of the seat stuff, as you raced around the city, and often the missions had various stages within them, and had you racing down Grove Street to your safe house with the cops on your tail, or Ballas firing at you from everywhere. Even GTA 5's heists were mundane and unexciting, and seemed very linear and straightforward.
The 3 character thing was a let down for me. In San Andreas, and even in the largely disappointing GTA 4, you became heavily invested in the central character, whereas I didn't feel the same way about Michael, Trevor and Franklin. Each had their own appeal, but by dividing the game into three stories, Rockstar made a big mistake. Perhaps if the story mode was longer, it would have been better.
The things that are good in the game, are the things you would expect to be good. The graphics are great and the scenery is fantastic and the characters move well, but as far as overall gameplay goes, GTA 5 is bettered by a game that released over a decade ago in GTA San Andreas.
The online part is equally as dull. It takes forever to earn any kind of money and this required hours of repetitive missions which gets old quickly. Plus there is the endless stream of douchebags who drive around in tanks and blow you over and over again.
I do enjoy the updates Rockstar have provided and they deserve credit for providing fresh content, but even these get old quickly. The updates themselves are fairly bland, you get some new clothes or hairstyles or a couple of new cars. This is nice, but it doesn't really improve the game a whole lot.