Our story happens to take place in a time where the White Tower and the rest of the world is rent with chaos, deception, and the general unraveling of the Pattern. While it's true, the Aes Sedai appear to be nothing but petty squabblers who poke their noses everywhere seemingly for their own personal gain, the combined history told by every character seems to indicate that, for most of the time since the Breaking at least, the Aes Sedai served were more or less a neutral society of channelers that kept, for the most part, power-hungry tyrants in check and attempted to keep chaos from sowing. Of course, that's not always the case, but if something crazy happened--i.e. a false dragon starting wars--the Aes Sedai were there to help. The fact that they had no intention of conquering territory lent a bit to their credence, I believe, and they do have a general principal: Aes Sedai means "servants of all" and, while they still aid any who ask, their aid comes at a price. Their manipulations exist everywhere, on every scale, so I'm inclined to think that the Aes Sedai have been both a blessing and a curse to Randland. There have certainly been instances where the Aes Sedai have helped, and instances where everyone would be better off without them.