The Treaty of Lisbon or the EU constitution reform treaty meets the need to reform the EU structure and function. The EU has currently 27 member states, with the Lisbon Treaty it will narrow down to 18 thus eliminating the pillar system (European Community (EC), the European Coal and Steel Community, and the European Atomic Energy Community), and the creation of a President and Foreign Affairs Office.
The Treaty of Lisbon will reform EU governance, thus it refines and strengthens the EU community as a whole.
No, the EU Constitutional reform treaty is not a good idea, because it is far too federalist. The United States got rid of their Articles of Confederation in favor of the U.S. Constitution. The result of that, only 200 years later, is massive federalism that is always getting closer to a police state. It is sad to see Europe heading the same way.