I would love to see some time travel missions with suitable rewards. For instance I would love to have my captain strutting around the ship wearing a suit from the 1930's/40's or whip out a tommy gun (with attached ammo replicator) and spraying those damn borg with bullets....wait didn't picard do this in first contact on the holodeck? Still my statement stands.
A brief list of rewards from missions:
1. 1930's/40's era outfits and weapons (duh)
2. Medieval era weapons and outfits
3. More early space travel stuff (Between Ent and Tos eras)
This is just a small list of what I would love to have, feel free to add more.
OH and being able to mount weapons and armor on display racks in your ship.