I can apply a region change

[silborynirmata]

It just lets me apply a region change, and does nothing. The correct behavior for this is to destroy the cluster and recreate it. This is likely true of subnet, vpc, and the like.

[JimBugwadia]

Would it be better to block and not allow the change?

[silborynirmata]

That would be better than the current behavior, but not expected terraform behavior. Terraform is not for the faint of heart. With AWS terraform for example if you change a region, vpc, AMI, or the like terraform will happily delete your current infrastructure and create new conforming infrastructure. There is a reason that terraform apply shows you a plan before applying. Personally I'm okay with either behavior just not happily applying bogus changes.

[JimBugwadia]

disallow region change