I am unhappy about the Scions having plot armour as well. As much as I love them, I don't think they deserve plot armour, especially in a scenario such as the one presented by Endwalker: The Final Days.
I am not someone who says that no character should ever die, but I am someone who believes that important characters, if they have to die, should have meaningful deaths and be properly developed before dying.
I absolutely adore Emet-Selch and I too would adore to see him again and spend more time with him in future patches and expansions. But I feel the same about Zenos, if even more so, for the reasons I've already listed previously. When Emet-Selch was first introduced in the patches between Stormblood and Shadowbringers, he came across as yet another crazy, deranged, dangerous Ascian. But in Shadowbringers his character was given a backstory and proper development, which continued in future patches and even now in Endwalker. My hope is that the same happens for Zenos, that he will come back and be properly developed, especially now that the main arc story of Hydaelyn and Zodiark is done. My hope is that now there will be more time and resources to focus on previously neglected characters such as Zenos and develop them beautifully. Ishikawa has shown time and time again that she can turn a character/plot around and make it interesting and meaningful. For example, take Emet-Selch. He himself was more or less a sociopath/psychopath in Shadowbringers since he actively participated in 7 Rejoinings which killed numerous people on both the Source and each of the Shards that had been absorbed. He built empires and let them collapse for the sole purpose of chaos. He killed and made countless people suffer over thousands and thousands of years. If anything, Emet-Selch's kill count is way, way higher than Zenos's kill count. Yet, Emet-Selch is now a beloved character because Ishikawa managed to write him thus, she gave him proper development. I believe that if she wanted and if she were allowed, given the time and resources to do it, she could also turn Zenos around.
"Where there's a will, there's a way. After all, miracles happen every day."