When I was trying to think of ideas that I would like to see in a new DLC the first one that came to mind is that I would love to be able to play a synth.
So off the top of my head, you enter a new area and in true DLC fashion are rendered unconscious, when you awaken you find that your brain has been transferred to a new synth and placed in a strange structure. You must now follow a voice accomplish tasks to judge how successful the
Procedure was. After many missions, meeting a new companion, unlocking new synth perks, taking down an evil scientist (who also created valentine) are given a choice. Be returned to your human body or continue in your new synth form.
Feel free to add on or critique.
Krimdule