VT-d, VT-x. 2007 != 2013. The number of hypervisor exploits is far fewer than the number of local root exploits on various shitty OSes (including OpenBSD).
Do you have a link for this statistic? Since I don't know of a local root privilege escalation since several years in OpenBSD, this is a quite high mark.
Edit: this is not a os-or-vm problem. You will have local problems and now, in addition, rooting a server may give you access to even more servers that run on your hyp.
