The switch
In all my years, never do I recall seeing another switch arrangement quite as complicated as that of the 64. When one considers that the 65 and cleaners before it all had a press-button switch fitted directly to the top of the cleaner, I fail to see why the 64 could not have the same. I am also at a loss as to why the 64 and 65 are so physically different in shape. Producing all those different parts for both cleaners would not have be at all cost effective. The only parts which were the same were the motor, cord socket, and dustbag. I think a 65 cleaner with lower wattage and plastic tools would have been just as good as the 64 as we know it. They could even have used the same carry handle from the 64 too if a different look was the name of the game.