so yi plus new rageblad equals unkillable but ornn cant have sheild and unstoppable on his w?

so i want to know whats up with rage blade new ability being allowed but ornn cant have a shield and unstoppable on his w. If ya going to put armor n magic pen on that item ya should let ornn keep his shield and unstoppable to survive that new ability against champions like yi. i melted like butter against a burning knife against that item.