That's a good point and is a good reason why people should pick based on preference. (though I still disagree that mouse has generally less control)
Kunino Sagiri wrote:the objective advantage of a peripheral with lesser total physical structure (tablet pen) in terms of control to something with more (mouse) at least for this game.Control as a metric does not exist without the context of anatomy and physiology. More precisely the control that a pointing device grants an individual is a function of both the physical properties of the device and the anatomical and physiological properties of the individual.
It doesn't matter if it fits your hand, it has a good shape, you prefer it or whatever simply because they're irrelevant.
While I believe your argument that the physical properties of a tablet leads to greater control is true for the majority of human beings, I also think that the difference between mouse and tablet is minor enough that a smaller portion of people would have greater control with a mouse due to some anatomical or physiological oddity.
Thus it would be more reasonable to say that tablet is more likely to give a greater level of control.
A possible reason for being anatomically suited to mouse is big hands, though I think mine are average.