People say he's bland, but that's just how they've chosen to perceive him. He does have a lot more depth. Although politics may bore him, he is willing to use politics to get what he wants (a challenge) and do a lot of smart stuff to make it go as planned. I mean involving The Moon in his plan? This is a smart guy, not a mindless cyclops that just wants to chase you.

He started off raiding Doma, then came to take over The Black Wolf's territory as well and carefully killed any generals in his army that did not themselves participate in battles. Terrible as it may be of him, it produced an army with pro-active generals that had been in battle and lived and shows his ability to rule.

He was fascinated by the idea that The Echo can be used to control and influence others, which he then used to control Shinryu, showing the side of him that is interested in science.

I can see how he gets reduced to being like a mindless cyclops that just wants to fight you for no reason, but he does have some depth and that depth has fascinated me, especially his interest in the science of The Echo.

You could argue that The Black Wolf was just like him while he was on his conquest. The desire to go around taking over territories and defeating powerful foes to make yourself more powerful is something instilled in a lot of garlean rulers from birth, so why would Zenos be any different?