How do you come to the conclusion that it could be better? Just because a game runs poorly, doesn't mean it's badly optimised. Some things just take lots of computing power and there's no obvious way around that. Also, I think people have a bad habit of slamming every graphical setting to its max and expecting perfect performance. You only need to reduce a few settings to get a significant improvement in performance for a marginal reduction in perceived image quality. This is not to say that the max settings are useless, it's probably a case that the improvements are so fine that you are simply are not noticing the increase in detail. This could be for variety of reasons (e.g. your screen resolution is too low to capture the increase detail). Of course, it could also be an issue that is specific to your system, but most people seem to be happy with the performance.