4. New Characters Can Be Introduced
The idea of a Time Lord is quite interesting in itself. A race of god-like creatures who can live through centuries on just one life, can cheat death and have the knowledge and abilities that can only be mastered after millenniums of training and study. Many of the greatest characters in the series are Time Lords, and some of the greatest stories in the original series also involve Time Lords. Not only that, but remember that when the Time War was at its highest point not everyone was in love with the Time Lords. After all, Cass chose to go down with her ship instead of travelling with the Eighth Doctor, and that's a pretty damning indictment right there. Let's not forget that there are many people that are willing to go to extreme lengths to prevent history to be changed. This plot point could be used to introduce new characters and races that could be either enemies or friends for the beloved Race.