This is all why I included "YMMV".
If clip gain envelopes changed the waveform display, in SONAR, I'm sure I would very much like it and use it. I think it's a great idea. But it doesn't exist in SONAR so at this point it's simply a missing feature. However, I still don't see myself suddenly not using track automation because of it - they each serve a purpose.
I guess in the end I don't find this missing feature absoutely "essential". Perhaps if I had used it all the time and then it was suddenly gone, I might feel different. But honestly, swipe and drag on automation lanes (with bright green envelopes) works OK for me. So does splitting clips and Ctrl+Dragging to adjust clip gain envelopes. Most of the time I don't want to affect what's feeding the track FX, so...
PS: I wonder if bus waveform previews might fit into this discussion too. Particularly when a group of tracks feeds a single bus, and the cumulative results are more important than each individual track.