Irrelevant. By definition, exposure value (EV) in photography is a number that combines aperture and shutter speed.
there will always be a need to adjust iso/gain
I'm asking about the on-camera user control over ISO, "is it possible to design a camera without an ISO dial?" The answer is "yes". In fact, there are cameras where the ISO dial does nothing, absolutely nothing, to raw data.
like a car
Car analogies are lame.
Instead, answer this:
Given you can increase exposure, would you increase ISO setting instead?