Steven Tyler is apparently no Simon Cowel. Sources say that amongst the group of judges he is closer to a Paula than a Simon. While Simon was the least popular judge amongst the contestants, he was the most popular by viewers. To keep the viewership is to keep the Simonness. His brutal honesty is a main reason why people watch and why contestants perform to the level that they have in previous seasons. Without that, there could be a drop in viewers and the level of talent.