Yeah, but wse don't know what he was before being governor of Omashu. For all we know, he was governor of a string of colonies. Generally, governing a newly conquered territory is hard work that needs a certain amount of finesse, and in historical empires, the successful governors of such territories could parley that into extremely high political advancement, so whoever got the post should be someone either skilled, or powerful. Since Azula thinks he's an idiot, and we haven't seen anything to contredict that, I'm going with powerful, especially since he was able to betrothe his daughter to the fourth in line for the throne, and that betrothal wasn't broken off when Zuko became crown prince. Plus, their house in the Caldera is right next to the palace. My theory is that Mai's father is the idiot son of some great dead general, and he's rich. Which makes Azula dissing him a tactical mistake, but one that it wouldn't be out of character for her to make...