Arbiter is only useful in rage, nerfing that is a very bad idea. He has a melee attack like the Chieftain, but he lacks the Chieftain's health. He has low health like the Prophet, but he lacks the shield and the long-range attacks. To make things even he has rage.

Arby is useless without his power, and his power is the most supply consuming. So now Arby players not only have to pay attention to their economy, but now they have to worry about what might be too much when raging to protect themselves.

The other leaders have vast advantages over the Arby, nerfing him in rage is a terrible idea.