I understand what you are saying, and while I loved GTA V I don't think it deserves a 97. I know more games get scores that should be lowered, given how they run, and that performance isn't everything. But damnit, there's bad perfomance in only some areas, like Dark Souls 1 (blight town), and then there's bad performance throughout the whole game (AC3). Not to mention the bugs and gamebreaking glitches. I might be overly agressive towards Ubisoft, but they didn't start this gen on the right foot, and their constant PR blunders and downgrades already soured so many people that it's hard to cut them some slack.
It's not a small studio like From or Tango: those studios I can cut some slack. It's Ubisoft with hundreds and hundreds of people working on this, on a huge budget. Rockstar is the same, but I still think their games have more scope, ambition and variety to warrant a better score. They've been trying to shake things up a little with each entry, and, apart from AC2 and Blackflag I can't say the same about the AC franchise. It's getting stale. But this is all my opinion and nothing more; I'm sure there are a lot of people who think the same about GTA franchise and that is fine, I won't say they're wrong. Everyone is entitled to their opinion.