Oh, I see what you're saying. I don't know man, I think a lot of power metal bands are just so generic. That's usually my problem with it. I think that a lot of power metal bands try too hard to committ to a formula, and when a band with no innovation tries to do that the consequences are horrible. It just sounds like bland, uninspired shite. I guess maybe some bands are able to recognize their best song and put it at the head of a record, and then throw on the rest of the tunes. I really don't have a solid explanation, but I know what you're talking about. Power metal really is a genre that has some pretty horrible, generic bands.
EDIT: Also, I think that most power metal bands know that there is a certain formula that defines power metal music, and I think some bands cave under the anxiety of writing a record full of awesome power metal songs. Not many bands can pull that off. So, lots of albums end up being sub-par.