No. The country has increased in size and the government now deals with far more areas than it did when there were 5 cabinet members. (The number of the cabinet members could probably be cut, but every department has its lobby and they are very vocifereous when threatened.)
The constitutional change that deals with the use of the electoral college as a rubber stamp for the popular vote was a result of party practices. The founding fathers were against this idea.
Under the United States Constitution, the President of the US has many jobs. One of those is to be the "Chief Diplomat" for the nation. He has the Department of State to advise him on foreign policy and foreign affairs. A good example of his job as Chief Diplomat was President Bush's recent trip to consult with our NATO allies.
article 3 deals with the judicial branch of the government
Article III deals with the supreme courts powers.
Secretary of Treasury
The Secretary of State.
In the US, it's the Department of Agriculture, headed by the cabinet post of the Secretary of Agriculture, currently Tom Vilsack of Iowa.
Multiple members of the Cabinet deal with foreign relations, however Secretary of State Hillary Clinton specializes in the affairs of foreign nations
Department of the Interior is head of Bureau of Land Management, US Geological Survey, and the National Park Service
The Department of Interior
The department of firemen.
In the United States Federal Government, the department responsible for dealing with financial matters is the Department of the Treasury, headed by the Secretary of the Treasury, a member of the president's cabinet.
The Secretary of State is in charge of encouraging trade with other countries and the United States. The Department of Commerce deals with trade among states.
The Department of the Interior.
The School Board Dean
Secretary of Interior (Ken Salazar).