As much as I enjoy all of them, I wouldn't mind them sunsetting Davison and Colin. Syl has a lot of potential (and one-off companions they keep peppering him with) still to mine at the end of his timeline. (Something they actually were good about doing early on, but of late it seems they're sliding back to using the companions available which is limited the far end. I want a good, solid end to him and Klein, for example.) McGann seems ever closer to a "final" story which would seal up his time, maybe give him some "time off." Meanwhile, every two years they can bring him in and add new Charley, Lucie or Liv stories in between what is there.
I can definitely see a transition away from the Monthly range soon to boxsets and more emphasis on the extraneous titles. As we noted, Moffat more or less gift wrapped Clara/Me for Big Finish and you could easily do Bill/Pilot adventures. Plus, 11 and 12 are untapped markets for the most part, and if they can get them in that would be the cream on top.
The only boat that seems like it won't come into port for them is Eccleston. They were able to get John Hurt!