we have 4 Ironport over 2 Datacenters. The 4 ironports works in one cluster and have the same OS version. In the future we will change the hardware because the C*50 models are out of support. The old and the new hardware have the same OS.
the new C *70 get the networkconfiguration of the old one Ironport and have no connect to the company network
one of the old C*50 machine delete from the cluster and shutdown (clusterconfig)
the new C *70 will be connect to company network and start the machine
the new c*70 will be member of the cluster (clusterconfig) and get all configuration of the cluster
the new C *70 works fine without big manuell configuration.
You hit the nail on the head. You should only have to deal with machine-specific configurations like network/interface and logconfigs. Perhaps a few others depending on implementation but as you said, the whole idea is to minimize individual box settings.