I don't get what you're trying to say. That because arena is a high end activity and there are overall more casuals playing random battlegrounds means we should balance around BGs and disregard the more "competetive" game modes? Do you want a Classic style system where your rewards (gear/title) come from pure mindless grind?
If that's what you want, I'm not opposed to adding something like this as a parallel progression system that gives you access to the same PvP gear.
But as sole progression or focus of the game this would probably kill the rest of the PvP community that remains. High end activities usually need to exist so people have some sort of goal to work towards (and as a means to measure their skill) that keeps them hooked to the game.