Hell, you only see a little more of Batman's face than you would Dredd's and that's never been much of an impediment.
Except some Batman movies have made a point of unmasking him at key moments, particularly in Batman Returns, where it was done very awkwardly and gratuitously in the climax. Even the '66 movie was written to give Bruce Wayne a larger amount of screen time than he usually had in the series.
As for Batman, I'm pretty sure in most of the films, Bats had at least as much screen time as Bruce and I don't think I've heard anyone say "I'm sick of that freak in the mask, I want more of that smarmy rich bloke!"
But the point is, we did see the lead actor out of the mask. It wasn't all mask all the time.
But if you want a more relevant example, how about the most glaringly obvious; Vader. Sure the films don't follow him around all the time but he had several rather powerfully emotional scenes across 3 films and the mask (which showed nothing of the actor's face) to say nothing of his voice being dubbed after the fact was never an impediment to realising the character.
But David Prowse wasn't a big-name actor. If they'd cast, say, Paul Newman in the role, you can bet they would've unmasked Vader halfway through the first film or ditched the idea of a face mask altogether. A famous face is a valuable commodity. It's worth money. If a studio spends a lot of money on a famous actor, they generally expect that actor to be seen. This is why Sylvester Stallone took off his helmet as Dredd. This is why Tobey Maguire was constantly unmasked as Spider-Man. It's about the studio wanting to get the most for their dollar.
In this case, it probably helps that, though Urban's star is on the rise, he's not a superstar like Stallone, not quite a household face, as it were. He's more a character actor than a leading man whose face on a poster automatically sells tickets or DVDs. So there's not as much pressure to make his face visible.
Cyclops never took off his visor...
He was visorless at least twice in the films: in the climax of the first film, when Magneto took his visor to force him to keep his eyes closed, and in The Last Stand when Phoenix was holding back his eyebeams.