Hi Hosh'ki,
This is not something that exists within Prismic and is not something that we are likely to implement. Although I've marked it as a feature request for the team to see.
The issue with disabling UID editing after publishing is that users will no longer be able to update this important field in the case of errors or changes, so it would be counterproductive.
A better solution might be a more robust publishing workflow with our user roles. This way Publishers can make sure Writers haven't edited this field.
I would like to understand your website application a bit better though to know why changing a UID causes multiple builds of the same page. What technology is you app built in?
We have also discussed showing old UIDs in an object in the API to build redirects easier for static websites and also gave an automatic workaround for re-redirecting from changed UIDs here:
Thanks.