Zenos doesnt need to be fix because, as many pointed before, he's the antagonist to the WoL and he works. Is he a good one? No. Is he bad because he's one-dimensional? He doesn't have to.

The best part of Zenos was when he was in the Elezen body doing something. Now all he does is being bored in throne while Fanandiel (weird name, wont bother) tries way too much to carry the scene.

Having Zenos motivation being having that transendent moment with the WoL is fine he should work more towards it or be more "active" like Emet and Elidibus were.

Honestly Im more intrigued in Fananandiel and what to fight him way more than zenos.
I want