I don't have enough info about Zero to either hate or like her at this point. I get the impression there are more things we need to learn about her before passing judgment. I always assumed the hat thing was supposed to be an easter egg referring to some old FF game considering how out of place it is for someone who's even more stoic in cutscenes than the WoL used to be.

Alisaie and Alphinaud are acting like teenagers. Can't hate them for that, just a shame SE will never let them grow out of it.

Who do I hate? Kan-E-Senna and her siblings. That's a trio leading a nation but keeping that nation enslaved to the whims of some elemental demons instead of growing a backbone to end the cycle.