Well, he's mostly suggesting using a user-space networking stack provided by your vendor (Intel's DPDK). But writing your own userspace driver from scratch is actually very simple -- I've done it for Intel's 1Gbps and 10Gbps cards before the DPDK was made publicly available. We're talking ~1000 lines of user-space code, and less than a month of work. Writing your own userspace networking stack is of course more complicated, depending on exactly which level of protocol support you need. Supporting say ARP or EtherChannel is trivial, while a production quality and interoperable TCP stack will be man-years of work.
But having written systems doing 10M TCP connections at 10Gbps, I strongly believe that you want to relegate the kernel into the role of a management system. Having the system split across the kernel and user-space will lead to unacceptable performance, pretty much no matter where you split things. And having the full application in the kernel would be a nightmare for development, debugging, and deployment. (And I sure as hell am not going to choose a pre-alpha research project over Linux as the base of telecoms systems.)