It is a terrible idea because the game will always change. The developers need to keep up and nerf/buff what they need to when they need to. Even if they don't make the right decision (cough cough nerfing hunter subclasses instead of Titan hammers cough). But they work it out most of the time. They need to keep doing this otherwise you would see one cookie-cutter PvP build with only 3 guns being used.