Well I have to say I agree with you in the sense that they are not inovators. But you have to keep in Mind Gamma Ray was founded by Kai Hansen, co-founder of Helloween, one of the most influencial bands in metal, so his vision continues in Gamma Ray, so again, I wouldn't include this particular band in that category. However, Edguy is a Helloween clone and they are no inovators but they are talented and they do have good material.
While Maiden was one of the bands that inovated and brought something new to Metal, their sound has changed little (once in SIT and SSOASS and again with blaze). If you are waiting for the next Maiden or Sabbath or Rush good luck because you won't find them. They are already out there, the Next Helloween are Hammerfall, Edguy, etc, the Next Maiden is already out there as well as the next Stratovarius (Sonata Arctica to name one). The "next" whatever won't be like the last band, it will be its own, an inovator. So happy hunting.
Just because they don't inovate doesn't mean they are crap. They are still original in what they bring to their music. Bands that are pigs to me are the ones that sell themselves (Metallica post black album, Korn, Slipknot) rather than write good metal (Edguy, Hammerfall, Rhapsody).