That's true, I was trying to be generous and add in some headroom for overclocking
As for convection, even the weakest fan can beat that easily, so the absolute direction of airflow only really matters if you're designing specifically to utilize convection in the first place. If you have a front intake and rear exhaust on your case, convection inside of the case is near meaningless.
Problematic in terms of maximising cooling potential per volume while maintaining compatibility. I obviously also assume this has been tested extensively if it is real at all, but nonetheless it stands out as an example of engineering for the sake of engineering (and partially for the sake of looking like engineering, of course) rather than aiming to make as optimal a design as possible. Design simplicity is not a quality Nvidia tends to favor though, what with the near infinite number of screws on their founders edition coolers, so I wouldn't put it past them to say "screw it, let's ignore complexity altogether and just make something we think is cool".