Why they couldn't get XenClient - a bare metal client hypervisor - to run properly is anyone's guess.
They came close with v5 - just a few missing bits like wifi support missing. Personally I'd much prefer to be able run without an OS stealing my resources. And ok you are getting some bolt-on management and control but beyond that it is basically another version of what Parallels, Oracle and VMware have been offering for years.
Sorry Citrix, but on this one...meh