All of WoW's focus currently goes into their raids, leaving no content for anyone else to do. This game is better all around currently for MMO players because they focus on multiple things instead of putting all of their eggs in one basket. Putting so many resources on one thing inevitably drains from other areas. There is a finite amount of manpower and budget to go around.
Most people don't play this game for the raids anyways. I believe it was something around 5%? As fun as it would be to have more extensive raids, I'm not sure that would be a smart decision from a business standpoint.
Problem is locking the open world mobs to a small group of people would cause the community to be at each other's throats even more than the hunts currently do. People used to sit in Dragon's Aery in FFXI for 3 hours with their bots spamming, waiting to claim. Those who didn't claim it would try everything they could to MPK(Monster Player Kill) those who did claim it. It fostered an us vs them mentality. I'd rather do mob difficulty scaling like how FATEs are.
And yes, you are absolutely correct when you say devs listening to complainers from the forums can sometimes lead to negative consequences.
