I don't think it's actually Nomura's fault for being unproductive, since he's actually always doing a crap-ton of stuff for SE (character designs for all FFs aside, he's been working on the VII remake for longer than we think, and he's been involved in all of the KH games we've had since the Versus trailers). I think it's the fault of the higher-ups who were pushing for this FNC gimmick to make people interested. Nomura may have had one, vague, creative idea for it and they were all like "okay, quick, make a trailer for that and we're doing it" and proceeded to hype fans way more than expected. Except they forgot to give Nomura more time to actually handle it. Remember that KH is SE's current biggest cash cow, and he's been managing it all this time. So it's not really safe to say he should be fired since I really don't think the Versus thing was his fault - at least not as much his fault as the company's management at the time (which, as we all remember, made pretty much all the worst decisions at that point).