I think there's a subtle balance between 'need' and 'integral to the game'.
Airpower has been almost completely absent from 40k, despite being a mainstay of the fluff and other systems. Obviously there are modelling restrictions, but GW have been able to produce sufficiently big enough plastic kits for at least a decade now.
I don't see a problem with fliers being a large aspect of the game; it's stranger that they haven't been part of it for so long. It would bring an additional variety and scope to the system.
So there's a potential for both sides to win. GW sell more kits and the shareholders are happy. We get shiny new toys that add depth to the hobby while not being a necessity.
Assuming of course that it all goes right. And I do genuinely hope they do get it right.
Hoping that GW messes up just so you get to winge and moan about GW is just.... ...bloody internet...