My first drpg was Etrian Odyssey 4 so I'm console biased, but to me because movement is so limited it makes more sense for A&D to turn like tank controls. To me it comes down to which action is more important, turning or horizontal movement, and ease of getting that input. Id argue turning is more important so I'd map turn to A&D/left&right and strafe to Q&E/R&L bumper because it places less stress to input more repeated functions while placing the less needed ones on more taxing keys.