I wondered how the thread was so long alreasy. Then saw the fate of the initial posts.

I care more about the quality of writing and acting than the exact person. Overall, for my tastes, these were poorer after Matt Smith joined, with one or two notable exceptions. The last few episodes of Tennant gave the doctor a vulnerability (and hence character complexity) that has been missing for a while.

Speculating on who might be chosen seems pointless - there are too many options, including lots of people I might not have heard of. But there are some actors who could really make something special of it - John Simm os probably ruled out because he was such a great 'Master' but I am sure he would be a fantastic doctor.   Andrew Scott ("Moriaty") would be another. I think it would be a good idea to have a doctor who was more mercurial which both these actors excelled at.