Some functionality I think would be nice to have when mousing over names in the friends or free company members lists:

If the player is in a party, show the party makeup in a tooltip.
If the player is queued, show a tooltip with relevant information:
- Party type (Low Level Roulette, Trials, which specific dungeon(s))
- current/required numbers of each role: e.g. 2/3 Tank, 3/6 Healer, 12/15 Dps

These are nowhere near vital, as one can always just ask what people are queued for. It would be convenient though.