A band should only be evaluated by the quality of their music. Leave the historical importance to the historians.
It seems very obvious to call a band whose historical importance overshadows their music as overrated. If that statement is not agreed upon, it would be akin to calling the caveman who invented the wheel the greatest inventor of all time. Or Roger Bannister (first man who ran the 4 minute mile) the greatest runner of all time. Or Babe Ruth the greatest baseball player of all time (let's face it, he probably couldn't last a day in modern baseball). Or the Model T the greatest car of all time. You get my point.
Yes, I get your point, and it's foolish. Your point is that Roger Bannister, Babe Ruth, and the Model T are over-rated because they don't have the skills of 2010, right? Let's continue: Mozart - overrated. Lots of people can play the piano as well as he could. Sure, the symphonies he wrote were excellent at the time, and hell, he may have started doing that when he was 5 years old, but you should only judge his brilliance as a musician by his playing. (That's what you're saying, right?) I think explaining your own analogies to you might help you realize how wrong you are.
But, just because someone is innovative or first, doesn't mean they're going to be considered great either. Rick Dees became famous, in part, because of disco duck. Singing like a a duck talking was innovative - and his song was a huge success. But, that innovation didn't make him great.