"Scale-Out" Primary Server
It would be really great if there was an easy way to decouple components that run on one large Primary Site Server and transfer them on to a number of smaller machines and be able to migrate those roles across machines quickly (similarly to how this is done in SCOM with Management Servers and Resource Pools). That would allow the following:
1. Simplify Maintenance - currently, every time we need to patch SCCM Primary Site Server, we need to agree upon the outage window with all the teams that rely on SCCM. If we could move the workload, we'd be able to patch SCCM infrastructure without causing any downtime, That would also simplify the process of upgrading the underlying OS of the servers.
2. Better performance - If we could see that components of our Primary Server are overloaded (i.e. SUP, or Inventory processing, etc.), we could just add in more instances for those specific components.