I think people are mistaking artistic style with graphics quality. You could take the same graphic artist and have him apply the same artistic style to a game on the PS3, 360, and the Wii and the game would very likely look significantly better on the PS3 and 360 even though the same artistic style was used on all three.
Also good graphics can help enhance the appeal of a game whatever it's gameplay. For example Spider-Man on the Wii had horrible graphics which turned off a lot of people even though the gameplay was relatively decent (from what the reviews said). Had the same game been given much better graphics chances are people would have enjoyed it a lot more. So what I'm trying to say is that good graphics are like good icing on a cake, if the cake itself is bad then chances are that the icing won't help but if the cake itself is good then the icing serves to make the cake even more enjoyable.
