The scheduling policy docs would be clearer if some diagrams showing how the migration works for each scheduling policy. The none and InClusterUpgrade scheduling policies won't need diagrams. vm_evenly_distributed and evenly_distributed can likely be combined into one diagram as they follow the same migration pattern but focus on different things. One on the number of vms and the other on memory and CPU load balancing. Diagrams already exist on the memory based scheduling feature page that these could be based on: http://www.ovirt.org/develop/release-management/features/sla/memorybasedbalancing/
The changes for this bug are now available: 4.1: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.1/html-single/administration_guide/#sect-Scheduling_Policies 4.0: https://access.redhat.com/documentation/en-us/red_hat_virtualization/4.0/html-single/administration_guide/#sect-Scheduling_Policies