Just out of curiosity, what's wrong with either of those two?
At that point, is Nomad still simple? If you're going to take on all of the essential complexity of deploying software at scale, just do it right and use Kubernetes.
Source: running thousands of containers in production.
Kubernetes uses etcd for service discovery. It isn't that Nomad does things differently or less simply, it is just that they are more explicit about it.
The real difference is that Kubernetes has a wide array of cloud hosts that hide the complexity from users, whereas Nomad can realistically be self hosted