I haven't run a ton of complicated DR architectures, but how complicated is the controller in just hot+cold?
E.g. some periodic replication + external down detector + a break-before make failover that brings up the cold, accepting any unreplicated state will be trashed and rendering the hot inactive until manual reactivation
Well, there you have to keep two systems maintained, plus keep Synchronisation/replication working. And you need to keep a system running which decides whether to fail over. This triples the work. At least.
E.g. some periodic replication + external down detector + a break-before make failover that brings up the cold, accepting any unreplicated state will be trashed and rendering the hot inactive until manual reactivation