Because every movie they make has to star Johnny Depp:

Anyone suspect this will be a revisionist take? The Lone Ranger will be a reluctant hero with some amusing flaws and quirks - Captain Jack Sparrow on a horse, more or less.

The original Lone Ranger had a Code, wikipedia tells us:

They'll probably go with the first, and leave it at that. Hey, it would be great if they went into straight-up non-ironic Heroic Mode like "Captain America," but I'm not counting on it.