Besides system requirements, it would be Awesome to rate games by how optimized they are.
Poor coding can mean you need a system twice as powerful to run a game compared to a optimized game - with the same complexity and visuals.
Like we need to know the miles pr gallon on a car, we should have something similar on games. I’d personally be much more inclined to buy a optimized game. Without some kind of system, it’s quite difficult to know before purchase.