I'd be fine if it still existed but was tied to... y'know, actual things, rather than being a stat. So, say a colony-revolution event pops in your repressive authoritarian shithole, some/all of the pops on that planet gain Individualist/whatever. Stuff like that. A world is right by the border with a friendly alien empire for decades, some of the pops gain Xenophilia. The same, except the empire is hostile and aggressive, so they become Xenophobia.
Tie it to actual events and situations is what I'm saying. That would be really cool. Even better if you paired it with sector improvements and could split off sectors with their own core ethos. So, say you've got three planets that are really xenos-friendly from the above, and they also had an event pop with a religious revival after the discovery of some holy artifact or whatever, in your materialist and xenophobia state. Split off a sector, designate it as xenophilia and spiritualist, and the pops within are happy and productive. Appoint a sector governor who shares those ethos (because why wouldn't leaders have ethos?), give them a good deal of latitude. But then you discover you've been too generous and forgiving, the division is so deep that the people of that sector don't feel as if they have a place in your empire any more. Do you enact policies to shift your ethos on a broad scale and deal with similarly broad discontent for a while, or do you risk that sector rebelling and forming a new state?
I'd love to see stuff like that, and it's an example of how ethics divergence and sectors could be tools used to allow emergent stories to form, instead of being annoying piles of shit like they are now.