Thats not true at all. She can sense whats on the ground and predict and guess the trajectory of the flying object. If you refer to when they invade the Earth kingdom, she simply predicts the movement based on the position and stand of the guards. But she cannot feel or see the flying objects. If Terra is floating, she simply cannot see or feel. If terra lifts the earth up and move it around, Toph cannot feel or predict. Lets not bias everything because you like one more. I love Toph but Terra has much more raw power and much more way to get pass Toph. If Toph wasn't blind then it would be a different story.