You can clear some/most/all of ICC in full toc gear and gear gotten from random heroics (badges). It's not hard to pug those things.

Those with resources and inititive will always make a profit in life, if you make a universal AH, that negates that possibility to make a profit taking alliance auctions and putting them over on to the horde one.

The world would be less real is blizz kept fixing every little imbalance. It's what makes each realm unique and "yours."