I must be old.....since when are bands like Edguy, Sonata Arctica and Rhapsody considered "power metal"? I thought bands like Vicious Rumors, Metal Church, Grave Digger and Brainstorm were "power metal".....you know, actually heavy. These other bands (Edguy and all) are fast, but they're not heavy. I've been confused by this term for the last few years. Oh well.....I guess times have changed!
Heard this talked about a few times and I think it has to do with a generalized contextual paradigm shift (god, that series of words looks way too heavy handed) that lies partially with the evolution of this branch of metal over time and the fact that the newest generation of these bands include a lot of gateway bands, i.e. young metal fans are getting into it through bands like Edguy, Rhapsody, etc. moreso than the old workhorses like Metal Church or Grave Digger. (I'm having a hard time explaining the idea I have in my head about this)
As a member of the demographic I just described, the bands in the group you mentioned are what I think of as True Metal or heavy metal. Other examples being Running Wild, Rage, Tad Morose, Virgin Steele, etc. To my ears, power metal, whose early pioneers I see as Blind Guardian and Stratovarius, just is not as heavy in general (BG was decently heavy but not so much when you compare them with your Grave Diggers etc). So you have your Skylarks, your Dragonforces, your Edguys, your Gamma Rays (GR isn't that heavy to my ears), etc. not to mention your folk metal bands a'la Elvenking.
The derogatory term I hear thrown at bands like Sonata Arctica on occasion is flower metal, i.e. bands that are supposedly metal but are decidedly un-heavy.
Side note for those on watch against the 'genre-police', this is just how I personally have viewed it, not trying to pin absolute labels on anybody.