The reason that the 16 team field was selected is the fact that you are qualifing for the state Dual tournament at the regional Individual tourn. There are times that the top two teams in each regional tourn. are not the top two dual teams. So we thought if we could take the top 4 teams from each regional that would almost guarantee that the best dual teams would get into the Dual State tourn.
The other way to do it would be to put every team in the state into Dual State Districts, and they would be required to dual all of these teams sometime during the season. Oklahoma currently does this.