I do see what you're saying. And to an extent you may be right - OK Computer could probably be correctly classed as 'superior' than The Bends under a number of different headings, be it melodic complexity, structural complexity, lyrical ingenuity, or even record sales. However, under the heading of 'music', there is no general measure of better or worse.
If I compare Paranoid Android to a recording of a three year old plonking out 'three blind mice' on a broken piano, I could probably name a thousand different categories under which Paranoid Android would be classed as better. But if you played both recordings for the parents of the kid, there's a very good chance that they're going to prefer the supposedly less 'musically good' crashings and wailings of their child.
To give you a personal example of mine - I like some of the music of
Daniel Johnston. I'm not sure if you know him, but he suffers pretty badly from psychosis, and records most of his music himself with just a guitar or piano, and an old cassette recorder. This can sound pretty lo-fi at best, and most people's first reaction would be to switch it off. Many of my friends in fact have - after I told one of them a little more about the guy, her reaction was "and they let him embarrass himself like that?", to which I replied "you think it's embarrassing, I think it's beautiful".
Put one of his albums next to OK Computer, and again, the Radiohead record would probably come out on top under most categories. However, if the sounds of the slightly unstable guy with the cheap tape recorder make more of an impact on me than OK Computer does, how can I honestly say that OK Computer is a superior work of art? I cant, and no one else can either, because art (including music) is created to make an impact on people - and without considering that impact, the art cannot be judged.