The theory that Stages would cause you to favor one leg in trianing is just that, a theory. Find some foundation that it would happen and its worth debating.
Well, my foundation for that was the Tacx ergometer. As I pointed out above, this was before I had a Power Tap so all I could go by was the Tacx and my HR monitor. My "set wattage" workouts were easier to complete if I pedaled faster (for any given gear ratio). My heart rate was lower, and it felt better/easier. So for a long time I thought "Aha! Higher cadence at the same power = easier! I should keep my cadence high!" So I was performing high cadence low torque (and, unbeknonwst to me, low power) intervals and, when I went for outdoors rides (where I had neither the Tacx nor an on-bike power meter) I followed that lesson.
Now, of course, I know better -- because I have a much more accurate and precise power meter. But if I didn't, I might be trying to spin at 100+ rpm all the time. Cadence was a red herring.
So it's not unreasonable to think that some people would "ride to the numbers" and look for ways to maximize whatever the power meter was reporting. This, however, wasn't part of our review. Ray had taken this aspect of the comparison off the table.