Why though ? They can just licence Ubuntu the way they want, they could do that with the distrib already.
They can't license Ubuntu any way they want, because Ubuntu is 99% software which comes from (and are owned by) other sources, not Canonical.
I have nothing against Canonical wanting to follow this. I do not like only one company being able to offer a different license (their CLA). So anything like that is a no-go for me.