The Ming also closed their borders, banned long range trade missions, suffered hyperinflation in the 1440's and beyond, levied oppressive taxes on the peasants that drove many of them to become Wokou, worsening the strain on their already selective trade and tribute, stagnated technologically and ideologically due to the reactionary and elitist Confucian bureaucracy and the emphasis on ancestor worship and traditional Chinese philosophy, failed to expand or make practical use of any of the technological innovations their predecessors had made, wasted massive amounts of money and lives on an impractical defense that in the end was overcome by bribery, and stifled social mobility at any chance they could. They were centralized, yes, but far from efficient (or competent, primarily in their latter days), and though the dynasty collapsing is not a reflection of their rule, it was a culmination of all their failings combined with a series of disastrous wars, and most historians will also be quick to point out those many failings in the midst of their triumphs as well.
Ming china after Zheng he expeditions had more pressing problems. After the Tumu crisis, the Ming emperor realized they had to secure their border and the frontier from the hordes (especially the oirats). However the efforts spent on the great wall and the increasingly corrupt military turned out to be a very costly matter, even though it did help fend off the hordes. Still, the dynasty ran into more and more economic difficulties until the arrival of europeans which spurred growth and increased trade in the empire. But again the Ming empire crumbled on the verge of bankruptcy when the little ice age, the natural disasters, the poor tax efficiency, and the imjin war drained the last resources of the empire.
Ming was never much isolated from the europeans merchants, even though they regarded them with contempt and showed little interested in importing european goods.
There are a lot of truth in these posts, a lot of it could be made into decisions or events.
For starters, the LA is somewhat of a good representation of the state of Ming during those days. Local authorities and lords held great power, some more than 50% I would say, example being the Mu Duchy. Essentially the Dali and Kunming area was under Duke Mu's control, as are most of the armies and officials there. The Emperor would tell the local authorities what needs to be done and hope they do it, much like orders given to vassals. On the other hand, some provinces closer to Beijing were clearly in the hands of the Emperor, and should not have 50%.
Ming was against trade at one point, because the first Ming Emperor considered it a dishonest profession of trying to gain money by making other people do the hard work. As such, Ming should not have any default bonuses to trade, which I'm glad to see one was removed. Ming did claim tributes, but as money was not the purpose of the expeditions, they often gifted back more than what was taken in a show of "Superiority".
Ming officials did not go with paper currency/cheques that were popularized in the Song dynasty, and instead went with silver as a standard for taxation. This was largely the problem that caused the massive inflation that was a large part of the downfall of the Ming Empire. Add an event that triggers with a choice to go with either, with bonuses or maluses and later events based on the decision.
One of the events in game was "Warriors do not read books", which is funny when it happens to Ming as it is most likely the opposite. This should be easy to remedy just for the flavor(Intellectuals do not contribute to War), maybe give it a choice of losing 20 military tradition or stability. Overall Ming should be a country that has generally low tradition, and events to get good Generals but also kill them off, especially when Eunuchs are in power.
Ming military was by no means weak when the fighting conditions were somewhat equal. The Tumu crisis did see a large Ming force defeated by a smaller Horde army, but that was due to a long chain of stupid decisions/things going wrong. A Manchurian Emperor was placed on the throne, but that was mostly due to the green standard army and other Han supporters deciding that was the better choice. Most of the fighting in the Qing conquest of Ming was done by defected Ming army, as by Manchurian accounts, Ming soldiers had a better understanding of fire arms and were better at fighting the Ming loyalists.
So as we mentioned above trade bonuses should not be included in national ideas for Ming, we should swap out ideas for trade and add artillery combat effectiveness. One of tactics Ming military adopted against the hordes was to have horse towed artillery that was armored against missiles. These chariots would be placed in formation which would protect infantry and return fire.
Ming should be given a special type of relation called Tributary, which would give a small fraction of their income in return for trade power from Ming. Ming cannot declare war on Tributaries or call Tributaries to war but are obligated to defend them(Korea starts off being one), otherwise losing prestige and maybe legitimacy. Tributaries do not cost a diplo slot.
Any country within trade range may apply to being a Tributary, and rejecting the request will have a negative effect for Celestial Empire(losing Legitimacy/prestige). This would have a diminishing penalty as the number of Tributaries increases.
This would give smaller nations around Ming a good way to avoid being attacked as losing legitimacy is lethal for Ming.