Here is an intriguing list of recommended changes to the Supreme Court, including expanding the number of seats to 19.  One goal of such a move would be that every president would then likely get a few appointments, lessening the fighting over each seat and bringing a wider diversity of people and voices to the court.  The author's main objection to 9 is that we have invested far too much power into a small number of people and often the one moderate who becomes the decisive vote.  Most nations now have far larger highest courts than we do and generally don't have the number of cases decided by one vote that we do.