For my part, GTA V was the disappointment of the year. SP is meh, MP is even more meh. I don't think I've played a single mission that was really good. Have to admit, I only have like 2-3 hours of MP gametime, perhaps it gets better. In SP I'm a bit further than the heist where the military is involved, and you escape on a train.
Even freeroaming in SP sucks bigtime. Terrible physics that's less fun than GTA IV, and a huge map with little to do. Flying helicopter is truly terrible. Just Cause 2 in my opinion have way better (more fun) physics of driving and flying than GTA V.
Combat is not even worth mentioning, mostly it suffers from using a controller. Maybe those that are used to it find it ok, but for me it's so incredibly much worse than using a mouse and keyboard on a computer.
Does anyone really think the graphics are good? Good graphics does not make a good game, but it sometimes help a lot. When I can stand 10m away from a door or some detail in the landscape and not see it because of jaggies and poor textures, it hinders the gameplay in my opinion.
But I think I just had too high expectations for this game.