I would write it in a different thread, because I just want to give feedback. But, since the score is bigger I decided to write it hear.
Civilization: Mongols
Score: 7284 (normalised), 1002 (original)
Winning date: 1450AD
Difficulty: Viceroy
Gamespeed: Normal
Version: SVN 594
Scenario: 600AD
Differences:
The SVN version gameplay has major differences from previous versions. The most important are:
*The new stability system: It is based on a core population vs historical and non core population.
*The new tech cost system: It is based on total population and not in number of cities.
*The new mongolian UP: Cities lose their defences and their cultural influence when mongolian army is in the next tiles in "revolt style" (defending units aren't damaged).
*The city-conquest effect: A part of the city culture is converted in yours.
These changes make a great difference in mongolian difficulty. AFAIK Leoreth reworks mongolian gameplay to be more unstable.
Strategy:
I switched to vassalage and guilds the first turn. I sent my troops to conquer china.
The chino-mongolian wars:
I used the mongolian UP as more as possible. Chinese had muskets, but without defences they are down in the second try at most. I conquered Tibet and Korea in the next turns. I discovered calendar to have access to luxuries.
I razed Hangzhou and the second Korean city (on the iron). I should have razed Kaifeng, but I forgot to do it.
The mongolian imperialism:
I rushed settlers in all my cities and settled all my core area. The research rate was really good, so I managed to discover music and started building culture in my cities. It is enough to control the 12% requested.
The western conquests:
You need to expand in the west. The reason isn't the land, you can achieve it without even Persia, what you need is cities for razing. I built gers in all my cities and after that only keshiks. I decided to go for India, because Mughals controlled Persia.
I razed Merv, Herat, Lahore, Balansiyar (or something like that) and that-city-next-to-the-tile-Gao-should-be.
I should keep Lahore, that-city-next-... and raze Delhi and Madras instead.
Aftermath:
Mongols should be less stable and have a lower tech rate for sure. The game warned me that I exceeded the domination population percentage limit and I was still stable and teching really quickly. I think it is really possible to win anything, an early domination a conquest victory, a space victory, and a score victory for sure at this point.
There were two reasons for this large stability:
*Economic growth:

and

were added in my economy every turn, so the economy was in +10 stability bonuses permanently.
*Military wins: I lost too few units, it the first mongolian game I managed to win straightforward without a single reloading. Well, this is great, and gave me a +21 bonus stability points.
Proposals:
I believe that the economy bonus will be removed when they stop conquests.
The winning stability bonus should be removed from Mongols. I propose that their military stability should not exceed 0. It is the same as chinese who can't trade their monopoly techs. The mongolian UP gives them a great advantage and it contributes in their stability in two ways making them extremely stable.
As far as the tech rate is concerned it may be better to begin backwards or let the chinese to build pikes.
Moreover, the 12% goal should be raised at 15% or even 20% (China, Mongolia, Siberia, Russia, Kwarezmia, Persia, Mesopotamia, Anatolia, Levant, Egypt, Pakistan).