I'm sure someone, somewhere was interested in my opinion on this...right?
Starting with the worst.
11: Colin Baker
Too be fair,, while Colin Baker was arguably the absolute worst thing in the whole of the Doctor Who canon (Eric Roberts not withstanding), this wasn't really his fault. By the time he took over the reigns and became the sixth Doctor, the show had stagnated. The writers decided to try to do a bit of a reboot and made the Doctor a manic, paranoid, violent, coward. As you can imagine the crowds ate it up like Crystal Pepsi. It is kind of a shame, as Baker was very excited to take on the roll, and had some ideas of his own, but the cards were already dealt. He was saddled with terrible story lines, an outfit that looks like a Jo-Anne fabrics vomited a sentient lifeform, and, most damning of all, an 18 moth mid season hiatus called for by the BBC's head of programing.
It all lead to the shortest reign of the original 7 doctors, and over all the third shortest of the 11 (behind #'s 8 and 9). If given a bit more time, perhaps the hero's journey would have been put into effect and we would have seen Baker's Doctor become a great man, but what we are left with in his three seasons is a sad shell of the Doctor's past, and the grim knowledge that Doctor Who was on borrowed time.
Here is a completely random sixth Doctor episode. I went random because they were all just as disappointing...
Several years into the first Doctor's tenure, it became very apparent that William Hartnell was getting a little old to be running thru corridors, or even briskly walking down them, and it was time for a change. A lesser show would have ended, or just killed the Doctor off and brought in a new lead. Imagine the surprise when the Doctor did indeed die, only to rise up as a goofy looking guy with a pauper's haircut and an Uncle Fester coat.
And thus is born the crux of my problem with the second Doctor, he is just the opposite of the first. Hartnell was serious, Thoughton was a clown. Hartnell was dignified, Thoughton played the recorder. I can't blame anyone for this, as it was the first time they regenerated the Doctor and no one had any idea what the hell they were doing, or if this was even going to work, but that doesn't change the fact that the second Doctor exists only as a foil to the first. And because of this, he is almost completely forgettable.
However Thoughton did give us the Sonic Screwdriver (that at the time could only unscrew screws...very slowly. Far slower than an actual screwdriver) and the Doctors love of Jelly Babies. So there is that. Also I feel he does redeem himself in "The Five Doctors" by not being nearly as annoying as the Fake Hartnell. So good on you #2.