Also, don't get stuck in the trap of thinking the solution to a service problem needs to be ... another service ("now you've got n+1 problems"). Such an abstraction layer would be much more effective (yet less monetizable) as a tool - c.f. the original terraform (non-Cloud).

There are already tools that attempt to do a limited form of this such as nixops, which attempts to devolve the ultimate power over someone's services to the user.