I'm still of the belief that Hydaelyn cannot be trusted. At least not fully. If Hydaelyn and Zodiark are two sides of the same coin then it stands to reason that they're both at risk of tipping things too far in regards to their respective element.

Hydaelyn doesn't need to be a straight up villain to be in the wrong. It could be as simple as her being misguided. The imagery and actions surrounding her possession of Minfilia, however, definitely reminds me of a parasite though. I recall saying as much around the same time that Minfilia was revealed to have been made into Hydaelyn's vessel.