Mormagil said:
that's not necessarily true. i can't think of any examples but there could always be some band that has an interesting idea yet fails to take it anywhere, then a "clone band" comes along and develops it to its full potential.
Then it's not a "clone'. In fact, you've almost just defined "progressive".
A clone to me is a copycat. It's a band that hasn't evolved the idea, hasn't morphed it, it's just a carbon copy. They've taken a formula and simply rehashed it but THERE ARE SUBTLE YET INHERENT DIFFERENCES simply because it's delivered by a different group of people.
Take some examples:
Helloween [Blueprint] -> Stratovarius [Clone] :: Blind Guardian [Progressive]
Bathory [Blueprint] -> Morrigan [Clone] :: Enslaved [Progressive]
Slayer [Blueprint] -> Lamb of God [Clone] :: Morbid Angel [Progressive]
The question is, do Stratovarius, Morrigan, or Lamb of God offer anything of value? I guess the answer is dependent on whether you like the "blueprint" in the first place.
Likewise, can you like Strat but not Helloween? Or Morrigan and not Bathory? Once, NAD told me he knew people that liked St Vitus and The Obsessed but not Black Sabbath.
Disclaimer: Results may vary.