I just think Hollywood has an avertion to completely masked cinema characters. With Darth Vader an exception, I find these days masked characters spend little screen time with their face covered. Just look at Spider Man. He can't keep his friggin' mask on for more than a few minutes.
That may have something to do with either the stars or the studio wanting face time. Stars want to be seen and the studios want them to be seen. Concern that the audience won't relate to a character who's nothing more than a "mask" might also be a factor depending on the situation.