Ok, people need to relax. I have yet to find a raid group where people are that anal about things. The general attitude is if you can do the job, you're in. Furthermore, warrior tanks can tank anything, even hard modes. The only difference becomes an issue of how quickly you can end an encounter (which is not that much of a difference to begin with. It's only a theoretical problem).

I know plenty of warrior tanks who are both raid leaders and great tanks. I honestly just see a bunch of QQ here rather than legitimate complaints.

Very few groups are gonna enlist a warrior tank who knows his shit only to drop him later if a DK tank offers to join.

"Hey , I know you want to tank this raid, but the thing is, despite the fact that you CAN tank this, a DK tank offered. And--how can I put this in a way that won't offend you--his DPS is slightly better than yours. It'll shave off a minute of our raid time."

Is it balanced? Not perfectly...but in the same way that one suitcase has 5% less volume than another one. They both get the job done just as well.