Proegress says it all. New elements in music. Creation of something new. The influenses will exist of course, but the main cause is to take the influenses somewhere further. You don't have to be complex to be progressive.
I mean how complex is "Parallels" from (the GODS) Fates Warning? Yet it is quite progressive!
And how complex is "Operation MindCrime". It is the definition (or one of the definitions) for progressive metal, though.
OK you anyone can clone Dream Theatre and claim that he/she plays progressive metal. Progressive my ass! This is regression!
Typical examples of really progressive bands that have taken their music beyond their influenses and put themselves years ahead of others from their style are:
- DEATH, ATHEIST, CYNIC for death metal
- CORONER, MEKONG DELTA for thrash metal
- CONFESSOR for doom metal
- QUEENSRYCHE, FATES WARNING, HEIR APPARENT for heavy metal
- ARCANE, SECRECY, HELSTAR for power metal
- SOUL CAGES, SIEGES EVEN, PSYCHOTIC WALTZ, DREAM THEATRE for progressive metal.
There are quite a lot groups that I could mention, but I will spend the rest of my day typing and, believe me, folks, I have no intention of doing that!
Well I guess the main question is how metal do these bands remain?
For a very narrow-minded metalhead like myself there is a lot of pain

seeing bands like Queensryche turn to grunge ways, or bands like metallica turn to oasis clones.
LET THERE BE METAL.