Nice job @Argent! I made something similar about Heralds and extremism some time ago, but you theory is better. I am strongly in favor of Ishar = Tezim, and your thoughts on Nale are the same as mine. Your idea on the Heralds being extreme opposites, or extreme personifications, of their traits, is nice. I think we might be able to find more patterns in there though. For example, your theory states that Jezrien might be the total opposite of leading and protecting, while Nale is the embodiment of being just and confident. That opens up for a nice pattern, where every other Herald is opposed to their traits, and every other embodies them. That would make Chana the opposite of brave and obedient, Vedel extremely loving and healing, Paliah the opposite and onwards.
I was onboard on Ishar = bald ardent, before I remembered that Tezim is still around. Also, Mraize comments about Ishar aren´t that big of an obstacle. He says Tezim isn´t human. Ishar isn´t either. He is a cognitive shadow. Mraize also says that if Tezim is human, he is not of the local species. but since Ishar isn´t human, that comment doesn´t mean much. We have pretty much on Tezim = Ishar though, so I find that more likely.