Referring to the most recent information, I find it difficult to believe "light" is all good, considering we're apparently going to be fighting "Sin Eaters" which I believe are the polar opposite of "Void Sent" that we have fought here and there so far.

Then there's "Innocence" which is apparently going to be a boss of some sort. While I'm unsure if Sin Eaters and Void Sent are independent of Hydaelyn and Zodiark, I think it's at least safe to say Light and Darkness are not "good" and "evil".

Hopefully we get to have some heart to heart with Zodiark in Shadowbringers like we've done with Hydaelyn. I don't think we can really come to any kind of a conclusion before then.