The rich-vs-poor argument doesn't serve his needs well enough, as there is no stark division between the two. He would have you believe that an individual making $200,000 a year is wealthy. In some parts of the country that may be true, but in the major cities where he needs the true strife to arise, this is middle-class level income.
The Republican/Democrat divide doesn't serve his needs well enough because of the rising number of Americans who choose to be independent of political affiliation because we realize that BOTH parties are to blame for our current state of affairs.
The Judeo-Christian/Secular-Progressive divide doesn't serve his needs because the overwhelming majority of Americans believe this to be a nation founded in the principles of Judeo-Christian morals and value system.
The Labor Union/Right To Work divide fails similarly because of the increasing numbers of small businesses and self-employed.
There are only 2 other divisions that Obama can utilize to his advantage, and they are both traits that we all carry with us from first breath to last--gender and race. If Michele Bachmann were running higher in the polls (and she may very well be in the future), she would be getting "Palin-ized" as well (and she may very well in the future).
Skin color is the last division that Obama can utilize for his ultimate desire, total power. Therefore, Herman Cain must be eliminated as a potential opponent in order to preserve this "nuclear option" of an all-out race war in order to achieve the goal of America's final fundamental transformation.