We may of course opt to discard only the elevator functionality and keep the turntable. That would already remove many unnecessary geometry constraints regarding the putative lower decks or the depth of the landing bay.
But if the shuttles really require a turntable to turn around, then it becomes rather implausible that they could move around the flight deck and the hangar decks on their own, into and out of the suggested forward elevators. And I don't really see why the shuttles could not hover to accomplish this, either on their propulsive systems, or then on dedicated antigravs, of the type familiar from many TOS episodes but now mounted on the landing pads.
I'd thus much rather do away with the turntable as well. Shuttles in all other Trek incarnations do appear to take care of themselves in this respect, despite lacking wheels.