Or for a real blast from the past , how about the original ST episode where Kirk and the crew go back to the 60's to stop the Nuclear rocket from being launched / tampered with .
That too. :p
How about bringing back Trelane (TOS: The Squire of Gothos)?
Did you play the old Star Trek game "Judgment Rites"? They brought back Trelane for one "episode", and this time he had a strong fascination with World War I aviation. The Enterprise even fought Trelane's Red Baron triplane in space! It had phasers instead of machine gun ammo. :p
These may already be in the game (I'm only a Lt. Commander), but:
1.) "A Piece of the Action": Where are the Sigma Iotians now?
2.) "Amok Time": Since my Captain is Vulcan, a "Pon Farr" episode would be a hoot. Heck, I'd really like to see more character-driven stories for me and my BOs (where a personal conflict in the BO's life is the driving force for the mission).
3.) "Shore Leave": Most latter Trek lacks this kind of trippiness, which is a lot of fun. Who wouldn't want to play a mission where you chase a giant rabbit?