Rather than use a cross fader to just fade between two looks, why not a full sequence of looks?
You could give the Run/Step toggle for sequence playback another option: “Fader”
In this mode the [Bump] button is toggled to fade fully the sequence in or out. The playback fader is used to step through the sequence, so in effect the fader and bump/go roles are swapped. As you move the fader from zero to full the output steps through all the recorded sequence steps, and steps back when the fader is pulled down. The more steps you have the smaller the fader movement needed per step.
This would give a very tactile control of a sequence.
Two useful adjuncts to this would be to allow sound to light to take over the fader action, so, for instance you could use your battens to give a bar graph level meter effect. If you had the wherewithal to copy the main cue stack’s looks into a sequence you could run through a whole play’s cues, stopping and going back where necessary if rehearsals are disjointed just by operating one fader.
It might also be a handy way to select a step for editing.