Considering the primary reason for the Dyna series to begin with was because it was an easier and cheaper way to isolate the engine's vibrations from the rider than would a total engine redesign of their Big Twin engine which would include an internal balance shaft mechanism, and something of which NOW I believe is in ALL Big Twin models, well, I can clearly see the reasoning for their decision here.
(...and as far as I know, besides the whole vibration isolating thing, the only other advantage the Dynas ever had over the Softails was that the Dynas twin shock system allowed for a little more suspension travel at the rear)
