It depends, we don't have a hard set criteria. Sound that "killz" is the main goal.
Some movies might call to be more front heavy because of heavy dialogue, which works artistically then the soundfield will open up. I think Kill Bill is good example of this, it's a little front heavy(because Tarantino loves his words) but it's still prime demo material.
Inglorious Basterds is like that to a greater degree, its just people talking in foreign languages for 2.5hours(and it's fantastic.) but at the same time all of the sound effects were spot on.