People are latching onto the logitech controller, but I think it's low on my concerns list. Controllers are relatively robust, and they stated they had backups, and could surface without any control input by manually dumping the ballast.

Much more concerning are the potential flaws in the carbon fiber hull, as disclosed during the David Lochridge lawsuit (mentioned in another thread), the rumoured lack of surface radios, the limited communication with the surface, the lack of any exits, and even the use of carbon fiber (which is strong in tension, good for high pressure tanks, but weak in compression -- not what I'd want for a submarine under massive compression)