The risk of weaker members banning together at any moment to take down the Dark Lord is too great, and an Order with multiple factions to manipulate is already weak and will fall to infighting anyways. The only benefit of a large order is strength in numbers. It can never operate from the shadows, and what is the point of greater numbers if each member is so much weaker? Quality over quantity. It's what he claimed, what he enforced, and pretty much what existed to make sure that no Sith would turn against the other, and in the end it left each Sith weaker than they could've been. At any time Kaan got too confident and attempted to place himself above another he was called out on it and slapped back down to everyone being equal. Except once again it did work, and it was that ideology that actually led to the Sith finally conquering the galaxy. Goals of the Sith: Destroy the Jedi- Achieved Conquer the galaxy- Achieved Yes it did work, it simply didn't last. Doesn't change the fact that the Order was the most successful out of any other Sith Order in history. The Sith were rewarded with the destruction of their greatest enemies and control of the galaxy. Bane didn't violate the Rule of Two.