I think making graphics worse is a terrible idea. There are maybe 1 or 2 actual problems with having good graphics, and most of the time the problem is based on how they're used. When used right, sexy graphics can immerse a gamer into the world even further. When used incorrectly and aimlessly, it can pull the gamer right out of it. For example, I really love the world of Red Dead Redemption. A lot of the reason for this is because the graphics make the landscape so real, that it looks practically like a high quality photo. The animation and the art style complement this (although there are some occasional hiccups, but those aren't there on purpose anyway) by looking realistic enough to create the illusion that his world really does exist. On the other hand, Fallout 3 has a very nice and beautiful looking landscape, but when you really take a closer look at the details, it reminds you that it's just a game. The animation and character models further bring you out of the illusion to remind you that you're just playing a game. This was my main concern with Fallout 3 (Though I really do admire many things about that game)
I really don't think that in either of those situations, making graphics worse would improve either of those games