alt Hacker News> whose only job is to say no to some other group
I suspect that people will miss just how precise you've been there.
Your proposal - if I understand correctly - is not just to spread the "ethics team" onto everyone (which is correct), but also to have someone in a dedicated role. However, they need to have not _just_ that role, but also some skin in the game.
This is also my view. These sorts of roles can have a very high impact and be very successful if everyone feels like they're rowing in the same direction.
The people in those roles need make people feel like there is value in seeking their input. They also need to find ways to say yes that helps things happen in the right way, rather than stopping them entirely.
This happens naturally in organisations where security is valued by everyone. InfoSec / CIO roles can operate very successfully and deliver a lot of value. As soon as people lose faith and see them as the "no" team, they start trying to hide from them.
There are lots of ways to create this but it's as much about the people in the role, as it about the organisation itself. If either are skeptical about the other, it falls apart very quickly.