Generally, people are too diverse to allow you to lord it over them without some serious force being used on dissidents, at which point you're not very Light anymore. The extreme case of this is people like Pol Pot or Robespierre, and Grindelwald is as good a fictional avatar of that sort as any.
Now, there are historical examples the other way - Cincinnatus, for example. But most of them you'll find will either have been given their power instead of seizing it(which is obviously a lot less likely to cause violence), or they'll turn out to be a lot less nice upon closer inspection.
Being a Light Lord doesn't necessarily mean ruling ordinary people and making laws. Unless you're like Harry and want to change existing laws a lot. Being a Light Lord is about leading people in the fight against evil and Dark Lords, but only a few people are fit to fight like that. For that matter, Dumbledore is a pretty good Light Lord, his goals just happen to be different from Harry's.
Edit: New thread posted here.
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 86. The previous thread has long passed 500 comments.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16.
As a reminder, it’s often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: