It was, and he was eventually defeated. Azeroth was still recovering when...

[He pauses for just a moment before continuing. If for nothing else than respect for how many lost their lives to Deathwing's rage and those who already fell in Pandaria]

Pandaria was discovered and there is conflict there now. The Alliance and the Horde continue to be at war with one another, and Garrosh- needs to be stopped. They all need to stop trying to kill one another.