Is good seems the obvious choice, but I think personally I would prefer to see a new character altogether. It'd be neat to have a companion that genuinely hates The Doctor, I think. That would be a cool dynamic, someone who has to travel with him but really doesn't want to.
Well, they kind of already did that. Her name was Tegan, she traveled with the 5th Doctor, and she was fairly intolerable.
What I'm hoping for is a companion who actually travels with The Doctor, staying on the TARDIS and not treating him as her hobby.
Tegan was annoying at best, but while she hated not being able to get home, she didn't hate the Doctor himself.
Turlough was another companion who, if he'd had his druthers, wouldn't have been there. He only asked to join the Doctor because of his deal with the Black Guardian. But as his story arc went on he became less cowardly and selfish, and ended up redeeming himself.
But I do agree with you about treating the Doctor as a hobby. With the companions in Classic Who it was all or nothing.
Well, she did have to travel with Adric...
Not after Adric died. And she did miss him.
Well, she did have to travel with Adric...
Honestly, I like Adric a lot more than Tegan. Neither is as good as the third vcompanion of that era. Nyssa (who never really got a chance), but at least Adric wanted to travel and wasn't whining.
Adric is actually fairly high on my list of favorite companions.
Nyssa, on the other hand, was snooty, boring, and had the most ridiculous taste in clothes. I'm surprised that Tegan, at least, didn't stuff some things in a suitcase and toss it out the TARDIS door just before they left Terminus... since Nyssa literally left in her underwear.
I'd like to see just about any old companions come back. I still say that they should have brought back Ian, Romana, Leela, and Commander Maxil in "Day of the Doctor." Tegan, Zoe, Jamie, Susan, and Ace are all classic companions that I would like to see again.
But if you had Commander Maxil, you'd have either had to have a regenerated version or a much older Maxil, given Colin Baker's age. And if you're going to have Colin Baker, the fans would have been upset if he hadn't played the Sixth Doctor.