Personally, I'd like to see more of the companions I already have, at least some of them. (I hate Skadge with an undying passion and he's the first companion I've ever gone out of my way to get negative approval in hopes that it will actually drive him off). I've already invested a great deal emotionally in these characters and while it was neat to pick up HK and Teek, my ship is getting a bit crowded at this point and I end up wandering through, clicking on Lokin and vainly wishing for just one more conversation with him. I miss talking about archaeology with Talos and since my Marauder dumped Quinn (backstabbing bastard) and hooked up with Pierce, I'd like to see a bit more to that relationship. Blizz will always be my all time favorite character, I would love to have more time with him. I've reached the point that I've held off finishing my conversations with Mako because I don't want to walk onto my ship and see that I can't talk to her anymore.
That said, if Jonas Balker ever gets tired of playing lackey for the SIS, I'm totally kidnapping him (mostly because I know it would piss off Jorgan. Then there's the string of almost-romance options we have across the galaxy- Aristocra Saganu, Phi-Ton (a Voss or Chiss companion would be pretty cool) are the two I can think of offhand that I wish I'd had a chance to see more of.
For the record (yes I know killing them was an option, I didn't), I thought Ivory and Watcher X were the two best missed opportunities to pick up companions in the game.
