I am sure the Nissan engineers have figured out the response characteristics of the wired steering systems vs. the mechanical one so the driver will notice little change when the backup / redundant system takes over. But the situation described by @Ian McMillan above does bring up an important issue. It would be nice to know more about this.
I like the idea of compensating for cross-winds; but experience in the aircraft industry (which uses triple-redundancy) has shown that unless fly-by-wire has some means of being very quickly by-passed when the voting circuit makes a mistake, you can find yourself in real trouble real quick. Split-second timing can be vital, can be life-and-death... I still feel the butterflies there