I have to disagree with you on that one. There are only a few on this list that didn't have very long runs as world beaters. This list is littered with the best of the best if you ask me. I only see a few real underdogs here.
From Wikipedia:
http://en.wikipedia.org/wiki/U.S._Open_9-Ball_Championships#Past_Champions
2011 England Darren Appleton
2010 England Darren Appleton
2009 Finland Mika Immonen
2008 Finland Mika Immonen
2007 United States Shane Van Boening
2006 United States John Schmidt
2005 Canada Alex Pagulayan
2004 United States Gabe Owen
2003 United States Jeremy Jones
2002 Germany Ralf Souquet
2001 United States Corey Deuel
2000 United States Earl Strickland
1999 United States Johnny Archer
1998 United States Buddy Hall
1997 United States Earl Strickland
1996 United States Rodney Morris
1995 United States Reed Pierce
1994 Philippines Efren Reyes
1993 United States Earl Strickland
1992 United States Tommy Kennedy
1991 United States Buddy Hall
1990 United States Nick Varner
1989 United States Nick Varner
1988 Puerto Rico Mike Lebrón
1987 United States Earl Strickland
1986 United States David Howard AKA Squirrel
1985 United States Jimmy Reid
1984 United States Earl Strickland
1983 United States Mike Sigel
1982 United States David Howard
1981 United States Allen Hopkins
1980 United States Mike Sigel
1979 United States Louie Roberts
1978 United States Steve Mizerak
1977 United States Allen Hopkins
1976 United States Mike Sigel