I'm not sure any waveform preview would make sense unless it was able to be done over multiple tracks.
Nuendo/FL do this mainly because then you can have the mixer full screen and still get a sense of the arrange page waveforms.
It's very cool but properly a beast on CPU via a script
what WOULD be quite useful maybe though is a "toggleable" small FFT window that you could enable to get a sense of where the tracks "energy" is or key/pitch at that time.
I only mention this since there are scripts that cover FFT analysis already.
Totally wouldn't be that bothered if not though
I think there are better areas Heda should spend his time on (my opinion only)