Thanks for the continued input on this item. We are taking a further look at this request, but it is not currently scheduled for implementation (we work in priority order, taking feedback from customers, here, and other sources).
An error occurred while saving the commentChris OB commented
Can't you use Cloud DNS server policies to set up an alternative nameserver? So your VMs will get the metadata service IP (169.254.169.254) as a DNS resolver, and then the metadata service will forward any DNS requests to a nameserver you configure in the policy.