The problem I have with is that those are two different philosophies to address the same problem. I have concern whether docker can pursue both of them at the same time. I see that sooner or later they'll have to decide which direction to pursue.
If they decide to drop containers and go the unikernel route, then a lot of what they already did to this point is no longer relevant. If go the containers direction then unikernel technology won't be too useful, unless using it to create hosts OS that would run the containers, but that is a huge challenge and at that point it no longer would be simple kernel.
Hit me up if you'd be into collaboration (we contribute back) with real customer partners of these things in production. I'm at the world's largest hedge fund with a massive use case that disqualifies Docker.
It's a very different technical approach but the use cases are the same: the customers who are interested in Docker will also be interested in unikernels as the technology matures. And customers who are sort of interested in Docker but unwilling to use it (either for security, or for performance, or because Docker doesn't isolate enough) may be willing to use unikernels.
A bad analogy could be made to Mac OS 9 and earlier multitasking, and Mac OS X multitasking: the implementations are wildly different but you keep (and gain) customers.
I hope this wasn't acquisition to simply kill unikernel approach.