I can convert vCenter Appliance 5.5 to run on Hyper-V 2012 R2 (boots fine, is network accessible), but it is not only not supported, but in fact does not work (configuration fails)
It seems that (unnecessary IMO) bits are relaying on Vmware specific modules/services etc (surely ie timesync does NOT need anything beyond ntp to work correctly - no need for Vmware own implementation!)
It would only be logical to have a choice. I personally like administering my whole infrastructure from OUTSIDE of that infrastructure. So if the lot goes down, I have something that is still working.
People can have different opinions of course. But I think being forced to only one option is too restrictive, especially that appliance is build with Suse Studio, which works perfectly on Hyper-V
Seb