So glad I'm not losing my noodles.
Certain features had to carry over from the original design.
Like the cockpit shape (which I believe had already been built) and the above and below quad-gun turrets.
The rest had to be radically different as the original model would be adapted to be the Tantive.
So I assume the quantum leap of the design came from those specific requirements (keeping the elements needed for the story and/or already built but making everything else look as non-linear as possible).
There is nothing less like a conventional linear plane layout than a saucer, one the reasons why they appear in so many science fiction stories.
And yes it does look a bit like a Vulcan salute too :-D