I was looking at this image and thinking about how odd it is that Batman's suit has absolutely no protection for his chin and mouth. It struck me, then, that Bane's headgear is exactly the opposite, protecting only his mouth (although I know protection is not the primary function of his mask).
This is a divergence from how Bane is normally depicted - in the comic books, Bane's face is completely covered. I guess the question "Is this important?" is unanswerable, because whatever interpretation I come up with about it is as valid as any other, so a better question is "Is there any evidence that this was intended by someone in production, or is it possible that this is a coincidence?".
Some possible interpretations in want of evidence include:
Bane's lack of inclination to mask his identity indicates loneliness (Earlier in the film, Batman says his own mask is not to protect himself but to protect his loved ones) although admittedly he does have Talia in his life
The opposite structure of Bane's mask to Batman's indicates that he is antithetical to Batman. This is in contrast to Batman's previous antagonist, the Joker, who spent the second movie trying to prove to Batman that they were more alike than Batman wants to admit. Joker also covered his face (with makeup) for the majority of the movie