There was an article on this very topic on Slate recently, I've put the link below.
Basically it points out that 3D is on a VERY steep decline as far as revenue goes and frankly I'm one of those who hopes the fad will die. I can count on one hand the number of films that have used 3D to its fullest extent and actually benefited the story in some way by having it.
The large majority of films that are 3D are fakes, just converted later, simply to get an extra buck. I'm sure one angle Hollywood was hoping was the death of piracy but as we all know, that did not happen. Personally when I see 3D I want there to be stuff popping out at me, the whole argument for subtle uses of it is pointless. This is film, if you need 3D to provide optical depth to make you feel like you're more involved in the film, then step out of the theater and go outside. While I love good cinematography, the focus should be more so on the story and the characters otherwise you should go to an art gallery and look at pretty pictures all day.
There is no reason Les Miz could have for employing 3D at all. If you want atmosphere, shooting in HD would give it a very gritty, real feel to it, kind of what the format did for Public Enemies. Most of it takes place in the slums of France after all!
Who Killed 3-D (Slate)