Regarding the increased ground clearance, the improvement was of course intended for deep snow conditions. On slippery roads the increased center of gravity is not making almost any difference for the handling since the resulting force between the vertical force from the car's weight (from center of gravity) and the horizontal force from the resulting friction of the tires will end well within the contact point of the tires and thus not create almost any roll or shift of force between the tires.

On dry roads, where the horizontal force is high it is of course important to have as low center of gravity as possible. It is however the quotient between the distance between the wheels and the center of gravity that is of essence (i.e. the resulting force), not the center of gravity alone.

I would guess that the E70 has a better ratio than the E53 here (wider track and probably not too much increase of the center of gravity), which theoretically would allow higher curve speeds on dry.