Based on what I've seen of him, I think Wrathion could easily become like a benevolent dictator - he thinks he's a good leader/hero/whatever, but has tendencies towards unilaterality and totalitarianism that could lead him to make decisions with terrible implications for life on Azeroth. I don't think he'd hesitate to extinguish all life on Azeroth, including himself, if he thought it would be the right thing to do.