The Isle of Thunder has multiple stages. These stages are unlocked through completing Isle quests. The stages advance the story-line of the isle. Progression is divided by faction - so it is possible, for example, for Horde to be Stage 3 while Alliance is still working on Stage 2. However, the system in place is designed to balance disparity so neither faction can greatly out-distance the other.
The Isle of Thunder has multiple stages. These stages are unlocked through completing Isle quests. The stages advance the story-line of the isle. Progression is divided by faction - so it is possible, for example, for Horde to be Stage 3 while Alliance is still working on Stage 2. However, the system in place is designed to balance disparity so neither faction can greatly out-distance the other.