Not really. You'd have loads of characters sending power-ups your way. When I play Mario Kart, I always shoot to the front within seconds- it was bad enough on MK64 with 7 characters firing hundreds of power-ups at you. With 16 racers you'd probably get slowdowns with karters of that polygon count. You'd sacrifice graphics for more karters, so 8 at the same time is good like every other Mario Kart game.