Plan 9 has had a very active development community during the past decade, nothing is preventing people from coming up with interesting ideas and patches, even to APE if that floats one's boat. Mixing different contrasting cultures usually just doesn't work, if you want POSIX, use a POSIX system, if you want Plan 9, go native, i.e. how the system was intended to be used.
Whatever suckiness Plan 9 has, it's either incomparable to other systems, or it is not worth caring about, or if it is, something can most likely be done about it with relatively little effort, and if not, you can always run multiple operating systems in parallel.
Running 9front natively on Thinkpad X230 as well as virtually on Qemu/KVM (9front supports both disk and net virtio). If you configure it as CPU server you can connect to it remotely using drawterm from Linux/*BSD/Windows for example and share files between systems. You can browse web pages unless they're maimed with js or css. Videos you can't view (yet) unless they're gif animations ;-)
Go attempts to bring the original Unix and Plan 9 innovative philosophy to the other systems, most importantly: simplicity, and doing things sanely from the start, not in a complicated fashion. You can find lots of material about Go on the internet, but one could list features like compact syntax, fast compilation, easy deploying (statically linked binaries), and easy networking and concurrency features (CSP). These are not necessarily "new" innovations but they are rarely utilized by other tools to same extent (Plan 9 being notable exception).