Yes, the EU constitution appropriately modernizes past EU treaties, because it makes the EU stronger. Just like the original articles of confederation in the United States, the original EU documents wre designed for consensus. They were not designed to give the EU enough power to be effective. The Lisbon treaty makes the EU strong enough to accomplish things.
Although the Lisbon Treaty has certainly modernized the governing documents of the European Union, it has not sufficiently democratized the union. Specifically, the citizens of the member nations have not had sufficient say in the E.U.'s decision making process. Government without the will of those governed is illegitimate and the Lisbon treaty does not ensure this for Europe.