When I was a kid, my favorite TV show as Kung-fu with David Carradine. The re-runs were shown everyday on TV and my favorite parts were when they did the flashbacks to Caine's time studying in the temple. One of my favorite scenes was when Caine would walk on the rice paper.
One of the core tenets of ashi-sabaki or footwork is how to step lightly, but balanced. If one puts too much weight in their feet then they are unable to move them fluidly and quickly. If one makes their feet too light then someone can sweep them out from under them. I asked Watanabe Sensei what the weight distribution should be and he said Furuya Sensei said that the weight distribution should be "50-50 but you should have this concentrated feeling of projecting forward."
We want this fluidity to our movement so that we can use our footwork to manage our partners advances. Sensei used to say, "If you want to speed up the movement, speed up your footwork." Ashi-sabaki is the foundation of our movement and thus we should put time into mastering it.
One of the tell-tale signs that one is stepping too heavy is if their step creates an audible sound when the foot lands. Losing one's balance or this audible sound are a few ways we would know if our steps were too heavy.
Here is a video from the Chinese TV show Kung-fu Quest where a student is going to train at the famed Wudang mountain temple. Take note of how light the masters step and how light their footwork seems. Pay particular attention to 25:00 where the Grandmaster describes "light training."