[5][6][7][8] Forrestal-class ships were the first examples of supercarriers and thus not quite a perfected design; their elevators in particular were badly arranged for aircraft handling.
The sponson-mounted guns suffered from poor range and complicated firing arcs, and were located in very wet and thus nearly useless positions in the bow and stern.
The redesign to an angled deck allowed a very large island, much larger than on previous carriers, giving unprecedented flexibility and control in air operations.
The most visible differences were between the first pair and second pair: Forrestal and Saratoga were completed with two island masts, an open fantail, and a larger flight deck segment forward of the port aircraft elevator; Ranger and Independence had a single island mast, a more closed fantail (as seen in all carriers since), and a smaller flight deck segment forward of the port aircraft elevator.
[10] This article incorporates text from the public domain Dictionary of American Naval Fighting Ships.