I agree, having a big man in the line-up is a prerequisite for a championship.
Jordan and the Bulls had Bill Cartwright as their big man during their first 3-peat. The Bulls traded Oakley just to have a big man. Then they got Dennis Rodman during their second 3-peat. Of course, The Worm can't be considered a big man but having led the NBA in rebounds per game for a record seven consecutive years, he should be considered as one.
The Cavs have Ilgauskus, Verajao, Joe Smith and Big Ben. Unlike the Sixers and the Celtics, Dwight will have his hands full. Lebron has ample "big man" support for his championship journey.