Right, in many cases, small is beautiful! I think that's what contributed so heavily to the massive success of the Xen platform. Is that what you mean?
Xen was successful because it was innovative, and because it worked around the fact that x86 was not virtualizable at the time. But after ten years of healthy competition, the only reason to prefer Xen to KVM would be things like QubesOS.
They also said the same about Xen, that a special purpose microkernel was a better choice than Linux as a hypervisor...