Abstract Storage Replica from the connection point
By putting the CAS server between the client and the mailbox this allows for the Exchange DAG to be replicated in 2 or more places but all traffic to the active storage location abstracted through the CAS server. This same concept in storage would allow all but one storage node to fail but the middleman would direct traffic to the surviving node. This could facilitate seamless failover between datacenters and remove any needs for an active/active concept in storage replica. The Exchange team nailed this concept and it would be great to see it brought to storage.