Insufficient error information when using the ARM templates deployment

Use of the ARM template to deploy the ARO cluster may lead to hard to debug error conditions:

1) Supplying already existing Resource Group at Aro_resource_group will result in "Internal Server Error" during deployment after about 1 minute of deployment. Using `az aro create ...` CLI will return immediately with clear error message:
`Invalid --cluster-resource-group 'xxxxxxx': resource group must not exist.`

2) Provision of the wrong client_id (but in the correct uuid form) with failure after about 10,5 minutes into deployment with the same "Internal Server Error". CLI command will return:
`Insufficient privileges to complete the operation.`

3) Attempt to re-deploy the template with the slightest modification (tested by adding a new tag) will result in the failed deployment and error stating that it's not allowed to change the RG for deployment. Evidently, I did not try to do it.
It's not possible to use recover the deployment afterward - it will remain in the failed state.

IMHO, ARM way of deploying the ARO clusters is not ready for production use.