I think your impression may well be correct, although I've not tried any Japanese rooms myself, only read reviews of them. For the operators I know, most focus

I think your impression may well be correct, although I've not tried any Japanese rooms myself, only read reviews of them. For the operators I know, most focus on 2) and 4). Most believe the puzzles are the core hook and must be well designed. Then they believe the puzzles have to fit the room theme. If a story can be squeezed in too, then they try, but it's rarely the driver. And gimmicks and wow factor aren't usually high on the list, but some operators (arguably us) do find these make customers want to play when they hear about them, so they're certainly not ignored.