When Guitar Praise: Solid Rock came out, there were one of two possibilities for this title. Either they choose to play DC Talk and Casting Crowns and sprinkle it with Flyleaf being the heaviest track, or they choose to go completely hardcore. Obviously they chose the former, putting their trust in draconian house rules rather than more free-thinking-heavier-than-the-original rockers. And I get that. I suppose "Christian Bands" are easier to market than "Bands-who-Happen-to-be-Christian." But imagine a band list like this instead.
The Devil Wears Prada
As I Lay Dying
August Burns Read
Maylene and the Sons of Disaster
Becoming the Archetype
Destroy the Runner
Then you have yourself a pretty awesome lineup in my opinion. And the best part is, they're all labeled as "Christian."
Sadly, stereotypes just market better.