Lines a different Doctor could have said, lines a different Doctor couldn't have said:
It got me thinking: there are some lines in Doctor Who that any Doctor could have done, although perhaps not as well, but perhaps sometimes better. But some lines, I think, would have fallen flat in the mouths of different actors/Doctors.
So, kind of as an open question: what speeches could have been transposed, and which couldn't have? Could the Tenth Doctor said "Good men don't need rules"? Could the Ninth Doctor made the "Time Lord Victorious" speech? Would the Fourth Doctor have insisted to Barbara Wright that "You can't rewrite history, not one line!"
It is a pretty open question, come up with as many examples, classic and revival, as you like.