I think you could estimate much more accurately with the prices of deeply out-of-the-money put options. Those are effectively a betting market on whether stocks will crash or not. We should expect option prices to take into account every major factor (not just these four), because if they didn't, people would get rich by trading on the "missing" info until prices corrected themselves.
Agreed, these are good indicators because people are actually backing these "predictions" with money...as opposed to theoretical models with no skin in the game.
