Rek'sai's burrow vision range

Every since i began playing rek'sai i thought of this idea about her burrow. It would make more sense that the farther away enemies are, the longer it takes for rek'sai to notices. Right now the entire area takes 1.5 seconds to recognize an enemy. I would like to introduce that at the outer area of the circle is 1.5 seconds, and as you get closer to her. The time it takes her to recognize enemies goes down. As i suggest she uses vibrations of the champions to track them. It would makes sense that the closer the enemy is the stronger the vibrations.