I think DD went a tad over the top with the footsteps in his vid. Clumping about like that wouldn't go down too well in silent running mode...unless the crewman took his boots off...which would be hellishly hazardous!
Besides, more seriously, noisy footwear is probably incorrect historically. Uboat shoes were lightly contructed (often canvas) with some sort of composite, or even rope, soles. Even the heavier deck boots had cork soles...although this probably had more to do with adhesion on slippery decks than sound abatement qualities.
If some sound mixing genius could come up with a suitably muffled footstep sound it could effective. But I doubt I'd hear it over the gramophone which I've usually got playing
