You're more likely to find a raid spot as fury warrior then a mage.
While there are a lot of furies out there already (same for mages though) most raids tend to take a fury over a mage if a decision has to be made (assuming there are already mages and fury warriors in the raid)... its just more consistent and far better scaling damage.

Even with pre-raid gear, a fury warrior will most likely deal more damage to a boss than a raid-gear mage.