I have heard a lot of people comment that one of the reasons that they like SUV's is that they like the driving position, i.e. they like sitting "higher up" where they can see in traffic. As opposed to the somewhat paranoid feeling that one gets in driving a low slung sports car where somebody in a Bro Dozer could chop off your roof (and your head) if they made a lane change without seeing you.
SUV's generally will also be equipped with larger wheels and tires and all season tires, an important factor for many. And people like the large hatch opening, fold down rear seats and high loading platforms for occasional cargo hauling, which is easier to use than a regular vehicle with a big trunk and fold down rear seat. Those are the kinds of things I was referring to when I used the term "form factor" for a theoretical Tesla SUV.
I expect all electric SUV's are going to be very popular in a few years and Tesla will be missing the boat if they don't have something in that category.