I lived through two mission presidents. The first one was very strict, but with reason I heard. Apparently when he came in the mission was in pretty bad shape. We were not allowed to listen to any music that was not in the hymnal or the children's songbook. My second president relaxed that a little in that he allowed classical music that was at least 100 year old. That was really nice.
I don't remember any other specific unique rules though I'm sure there were some.
We had all kind of policies and rules. One in particular came from Elder Ballard:
Talk to 10 people on the street a day
Teach seven discussions a week
Give 3 Book of Mormon books away a week
There were some others that I can't remember right now.
I don't think mission presidents should create their own rules. All the mission rules are in the White Bible. Joseph Smith said that we need to teach correct principles, and let others govern themselves. I think the same should apply to missions as well. The mission president in my mission before I got there had a ton of rules, and the mission hardly baptized anyone. Then my president came in, did away with all the extra rules, and the mission doubled it's baptisms every year he was here. Coincidence? I think not.
I understand what you"re saying Superfly, however all missions are not equal, what will work in one might not work in another, this is one main reason to localize the rules. As far as the "challenge" type rules, like the number of people taught, baptized, etc"¦ the question comes to what do you do if (When) you reach the goal? Do you stop, or continue? Sadly, once the goal is met, many people are unmotivated to continue at the same pace.