I struggle here, some had better writing than others, some I have personal feelings about because they followed others, etc.
I rated them based on charisma, intelligence, range of character (ie are you one sided, or can you adapt to different scenarios), and value to the franchise. #4 Easy choice, Tom did everything. Tom lasted forever. I died a little inside when he left the show. #1 This was hard, I loved Sylvester. But Bill did more for the franchise, and excluding his difficult persona for other actors, he was the most intelligent, had surprising wit/charisma, etc. #7 The most Tom like, after Tom left. Great range of character, smart, witty, funny. Mel deserved to die over Adric, but he had Ace had great chemistry. I wish that had gone on for multiple years. tie---#2, #3 I can't break this. Every time I watch or read a Jon story, he goes ahead, same for Pat. If I had to, I think I'd lean to Pat, as he had to do the essentially never before done task of replacing the main actor in a TV show...as the same person. And keep all the fan, and grow new fans. Jon wins in range of character in that he was more athletic and I liked his, banished on earth, working with UNIT, (cheap to produce, ahem!) time as it built characters like Lethbridge-Stewart. I liked Pat's wit and intelligence, as a smaller Doctor he couldn't run and fight, he had to use his personality to resolve things. #5 Poor Peter. He had the second most difficult transistion, following the legend. I hated him for years. Because he wasn't Tom. And he killed Adric. And he had two of the worst companions, Turlough and Teagan. And some really, really bad stories written around them. But 25 years later, you reflect and re-read his stories and re-watch his shows, he couldn't be Tom, he had to be someone else. Just like Pat didn't want to be Bill. He added charm and athleticisim to the role (Pat). Peter added a more serious persona. He did the best he could with terrible writing. And lame companions. And a dying show. The Master I'm trying to find people who would have been better Doctors than Colin. Colin was a useless, rude, clown. #6 I hated Colin from the second he appeared. I had high hopes of getting a Tom-like Doctor back. Fun, exciting, charming, witty, athletic (someone has a man-crush on Tom). Colin was none of those. Having dissed him, I don't know how much was his own personality and how much was production trying to take the role in that dark, lame, direction.