One of the unique aspects of the United States was that she was designed without an island on the flight deck. Most carriers that have been built have been constructed with an island amidships of varying sizes. The main problem with the lack of an island it that the functions performed in an island (air traffic control, combat information center, steering, among others) have to be moved belowdecks. And while this provides greater armor, it denies the captain, air boss, and others a view of their surroundings. The other problem with the lack of an island is that there is no place to locate radar and communications antennas.
However, what was probably the most interesting feature of the United States was the fact that she had 4 catapults on the bow and amidships, and yet was designed to be able to recover aircraft at the same time she was launching them. This was a capability not available for the U.S. Navy until 1955 on the USS Shangri-La with the SCB-125 upgrade for WWII-era Essex-class carriers. And even then modified carriers could only use 2 of 4 catapults when recovering aircraft.
What sank the United States however, was inter-service rivalry. At the same time the United States was being designed, the Air Force had begun pushing for a fleet of B-36 Peacemakers to use in lieu of carriers for nuclear deterrence. The SecDef at the time, Louis A. Johnson, canceled the construction of the United States 5 days after her keel was laid (see picture above). This led to the famous "Revolt of the Admirals" which cost the then CNO Admiral Louis Denfield his job. However, the "revolt" saved carrier aviation, as the then-new thinking was that strategic bombing with nuclear weapons would win any future war. This was proved wrong in the Korean War a year after the United States was canceled.
The USS United States was a revolutionary design, and could have altered the design of U.S. Navy carriers for many years afterward. However, at the same time, it might have been a good thing that she was canceled, as she was designed with nuclear deterrence in mind, rather than air support and sea control which have always been the traditional missions of an aircraft carrier.