Unfortunately, the center of the hood is a "low pressure" area, and the opening on the shaker scoop is just about dead center on the hood. What that means, is that the shaker scoop will not always be able to supply amble amounts of air and that makes keeping the fender snorkel a necessity.
A really well functioning scoop usually has its opening either at the front edge of the hood (Firebird WS6), the rear edge of the hood (Cobra), or raised up high (dragsters). Basically, locating the opening anywhere else the air pressure is higher.