I was thinking, if a new companion were to join the TARDIS while Jenna was around, wouldn't they seem a bit like a stranger? After all, Clara is no ordinary companion, to me she is neither Elevens' or Twelves' companion, she is the Doctors' companion. She was there when he almost reached the end of his regenerations, she was there when he "died" at the hands of the Great Intelligence, she is the one who split herself into multiple selves, she is the one who sewed the seeds into his brain at a young age to be brave and strong, she's the one who found true love and basically tried to hold his TARDIS ransom to get Danny back, she's the one who once knew his name, kind of.
What I'm saying is, they've got something special and have known each other for a very long time, he's like her family now and she's the one who can make 12 smile. It could be a tough place for a new person to join and fit in. I think Clara would get jealous and a new person may feel like they walked in on two old friends.
It would need a special set of circumstances I think to accept a new companion on board right now. My thoughts .....
What I'm saying is, they've got something special and have known each other for a very long time, he's like her family now and she's the one who can make 12 smile. It could be a tough place for a new person to join and fit in. I think Clara would get jealous and a new person may feel like they walked in on two old friends.
It would need a special set of circumstances I think to accept a new companion on board right now. My thoughts .....
I already want the next showrunner to leave and the 16th Doctor to step aside