That's just plain *dumb*. Fantasy lore indicates pretty specifically that everything looks *different*. That really powerful magic items are either absolutely beautiful or incredibly plain-looking, not chosen randomly from one of four universal designs.
Another case in point: Uniques. They go to the trouble of making these things called "uniques", then make *one* unique of each type. So you say things like "oh, *that* unique weapon again. I've seen that one before." Yeah, okay, so they *do* have custom graphics for some of them (luckily), but come on, would it really be that hard to add another few uniques of each type? And it would be so much more *interesting*, because a unique would actually be surprising and interesting, instead of "oh geez, don't tell me I got another Nagelring" and entire bands of warriors wandering around with - count them - TWO "unique" "Stone of Jordan"s EACH.