When doing a comparison of the Sixth and Seventh Doctors, it seems that they are actually pretty similar, with Seven being a more toned-down version of Six. But Sylvester McCoy’s Doctor had many dark, ominous moments of his own, and they were made all the more chilling because he did not have a threatening appearance. Much like the Second Doctor, Seven had a jovial personality and could be a bit of a clown. But get on his bad side, and you would see how intimidating a Time Lord could be.
A prime example of this was in “Remembrance of the Daleks”–after all of his encounters with the Daleks, he had no patience for them anymore. In fact, the plot itself almost seemed to foreshadow the Time War…and if this was just a preview, it gives us just a tiny glimpse of what the Doctor endured.