it's not abolishing it. It's an option to shields in the book...allowing you to assign the strength of the shields/screens to each hex facing as you want. So if you take shields 2, this would give you 12 screen points to assign around the ship allowing you to do 3 forward, along the sides and 1 rear....essentially the same thing as what you're talking modification thereof without needing any additional rules.
Except it doesn't standardize the approach among all ships so it doesn't solve the problem. If someone is free to take traditional shields (same strength all sides) then you've gained nothing in terms of game play.