Well I am used to the way it is. And I use my ears to decide these things. I wont say its not nice to see a wave change but to me it has never been an important thing to have. I would never rely on a picture or any other visual when I have ears as my ultimate acoustic device.
The example about fades in Sonar is a good one for me. Though the option is there for it, it adds nothing to using a line and then confirm with listening.
Whether a line or a change in wave form it still boils down to how it sounds.