They are simpler but keep it mind all the other things you get from running on Mesos, like provisioning your services, having your services restarted when they crash, workload migration when machines fail, bin-packing so you don't waste resources, etc.
In both cases the combination (SkyDNS + Etcd or Consul) looks far less complicated than Mesos, so I don't really see what you think you gain. If you already have other reasons to want to run Mesos, sure.