neb: The fact that the whole RISC-V ecosystem is such a fixer-upper mess of duct tape and baling twine. Every time I work with one of these things I end up spending hours and hours patching and kludging things via USB-serial debug consoles and semi-documented contradictory hacks in support forums, and even then things only sort-of half work. And every time they abandon the current hardware and release something new you're back to square one with kludges and duct tape again.
This is the reason that has so far always put me off the, actually usable RISC-V.