[Spoilers] Why Zenos is the most important character moving forward

[Edax]

They can mitigate at least part of my issue with Zenos if they actually have him do things of consequence, make him a force to be reckoned with driving the plot and not just waiting for us to get strong. It still irks me that he stomps us i RR and the game 'tries' to play this off as a devestating defeat but how bad can it REALLY be if the resistance is able to hold onto that base of operations after the attack? Then in Doma when we lose to him, there are no consequences. In fact it plays into our favor because it ends in Grynwaht arriving at just the right time to help rally the Xaela against the Empire.

I'm not saying Zenos has to kill a major character every 5 minutes but if they're goign to play into the threat he poses he needs to actually do important and devastating things, again with Kefka as an example.

The problem with Zenos is that we never see him earn his power. It is effectively a form of Diabolus ex Machina, the counterpart to the Warrior of Light's Deus ex Machina (blessing of light) which are tropes of bad writing. If Zenos has all this power because the writer says so, and the Warrior of Light has all this power because the writer says so, then we're effectively entered a story equivalent to a 5 year old banging hero/villain figures together.

3. He is truly our perfect antithesis.
We are both two sides of the same coin. If the WoL ever gave into their bloodlust, the thrill of battle and used a might makes right philosophy, we would end up as Zenos, while the opposite can also be true as well.

No, he is not our antithesis. If the WoL gave into bloodlust and might-makes-right, at the very least the WoL worked for it from the ground up and earned that might through countless trials and tribulations.
To quote the wiki "Since Zenos never found challenge in battle" - https://finalfantasy.fandom.com/wiki/Zenos_yae_Galvus
Because of this, the WoL could never become Zenos. WoL progressed in power and understand while Zenos has not.
Zenos also has no arc. He became the strongest villain without sacrifice or confronting any personal demons, his character has remained static the entire time.

If I were the writers of FFXIV, I would move the story away from the Echo and Blessing of Light as fast as possible. Zenos has nothing to do with the Light vs Darkness conflict so they shouldn't be using those tropes with him. At the moment Zenos is almost a placeholder antagonist, someone so one dimensional he does not exist for any other reason then to confront the protagonist. If the story is going to be well written, they need to give Zenos some development. As it stands, Omega ends up having more of a character arc then Zenos and Omega only function in SB was to literally "test" the WoL. We've already done the the antagonist tests the WoL in a contest of power story-line already.

Omega went through a journey of self-transformation in an attempt to better them self. Zenos Fantasiaed into a new body because he was bored? Then Fantasiaed back because he was bored? If Zenos was meant to be a biting critique of WoL who fanta and buy level skips then it falls flat because I've never used either of those things.