Besides time and pitch it would be great to have a classic tape mode for time stretching as well (compare Ableton Live's Re-Pitch, Bitwig's Repitch or Cubase's Tape mode).
Explanation:
Re-Pitch Mode (taken from the Live manual)
"In Re-Pitch Mode, Live doesn’t really time-stretch or compress the music; instead, it adjusts the playback rate to create the desired amount of stretching. In other words, to speed up playback by a factor of 2, it’s transposed up an octave. This is like the “DJ stretching method“ of using variable-speed turntables to sync two records, or what happens to samples in traditional samplers when they’re transposed."
Tape Mode (taken from the Cubase manual):
"Locks the pitch shift to the time stretch as if playing back a tape with varying speed. If you stretch the audio material, the pitch decreases automatically. This variant has no effect if you use it with event transpose or the transpose track."
As Studio One 3 uses zplane's Elastique algorithms as well I hope the addition of the "Tape" mode / algorithm shouldn't be that complicated.