The open world action adventure genre could be so good imo but it just isn't. I just finished GTA 5 and was more relieved it was over than anything. The final missions were incredibly tedious and more trial and error than anything dropping items, fighting your way through waves of enemies, switching characters etc.. GTA IV was kind of the same thing to me although GTA 5 was even more tedious. I couldn't help but thinking this is not fun as I was finishing the game because it wasn't.
The actual enjoyment of playing GTA 5 was somewhere between taking a dump and driving home from work in heavy traffic. Yet this game gets 9's and 10's.
Free Roam and open world great. The actual mission structure is terrible. I had more fun with Sleeping Dogs which was much more straightforward and had a mix of fighting and driving and even that wasn't that great.