Or once you reach gold king you can move on to things worth more than gold. Like platnium, emeralds (yes knight, they can be worth more than gold), and diamonds. SO the highest rank could be the Diamond King.
Most of us have agreed that would bring down the quality of the rank system.
As for after Emperor, I'm not sure if there's anything after that. I've also thought about maybe they could revamp the entire thing, and add some in the middle. The only problems are 1) it would bring a lot of people down, and that would tick some people off and 2) people would have to re-earn ranks. Which would be a bit odd.
So all in all, I'll have to put more thought into it.
Say a person is a wooden knight, but the new system would bring them down. Well, what if they were just bumped up to the exact amount of points needed to be a wooden knight?
just make like platnum for them all then it would take make ime to do it because they would lose ranks because there are ranks benethem so they would have to higher the point value