Im not sure unikernels are a better solution. The texhnology has a lot of promise but the tools are not there yet. For instance running MySQL as a unikernel is possible but it's much more difficult than a container.
So "better" is quite subjective... more secure? Sure, easier to deploy and build not even close.
So "better" is quite subjective... more secure? Sure, easier to deploy and build not even close.