This is a big change. Now the other tanking classes will have equal ability to ranged taunt mobs off other players, pulling the mob to them. Often times warriors and druids have to either Intervene or Charge around in order to taunt a mob, and that can lead to a whole kaboodle of mobs following the tank. It often is not the ideal situation, especially if the mobs cleave or otherwise do AoE damage.
Now the whole process is simplified immensely and made much more efficient. Quite an awesome change, and one that has put a smile on my face today.