+1 with vmware support request opened for this issue.
Release notes state:
vSphere 5 Storage vMotion is unable to rename virtual machine files on completing migration
In vCenter Server , when you rename a virtual machine in the vSphere Client, the vmdk disks are not renamed following a successful Storage vMotion task. When you perform a Storage vMotion of the virtual machine to have its folder and associated files renamed to match the new name. The virtual machine folder name changes, but the virtual machine file names do not change.
This issue is resolved in this release:
From the above, I think it was a fair assumption that we would have the vm rename functionality restored as it was in 4.1
We need this as inconsistent file names cause problems with our backup solution. I can tell my vm admins not to rename vm's until I'm blue in the face but they still rename vm's at will. Backup team not happy and blaming vmware team.
My vmware Support Request # 13273587501 - I will document my experience here.