Variable playback speed
As a professional audio editor with a large roster of clients, moving fast is a must.
Hotkey "L" helps me do this but if we had adjustable playback speed without affecting pitch I think it would help dialog editors around the world do a more accurate job even faster.
This is present in competing products (e.g., Audacity). Allow listening to recorded audio at a customizable speed (125%) without effecting the audio. This speeds up the audio-editing process.