The recent series of the Doctor is focussed on his death. In as much as there are elements around the identity of River Song, the role and purpose of Amy Pond and where Rory fits into everything, there is no getting away from the recurring factor surrounding the death of the Doctor.
Talk of the Doctor’s death would inevitably bring around the mysterious subject of the mortality of the Doctor which is also brought up in his ability to regenerate. It’s not the first time I’ve brought up the subject meself, and I doubt it will be the last. this video provides an intriguing look at how the regenerations have been handled from Hartnell/Troughton to Eccleston/Tennant. There’s a lot of respect given to the latest work, whilst there is a slating for the McCoy/McGann one. As I said, intriguing approach, not one I necessarily agree with totally, but one still to take on board and appreciate. Enjoy.