Although it seems definite that Karen Gillian won't return to DW next season, and it's unlikely Arthur Davril will back- it's not
Certain that some form of their characters won't return- either older or younger.
I really want to see how this new Doctor will grow without Amy and Rory. They're so connected, but it would be great to get a new start.
John Barrowman has hinted that Capt. Jack may be back on DW next season, but I doubt he's the full time companion.
Any past companions you'd like to see return? I'd love to see Zoey return (with a new actress of course) she was from future remember? The distant year 2000! LOL. Hot karate chick in a sparkly jump suit= awesome.