I think the situation can be summed up as:
People are upset that the mechanics are bugged, that they can be unfun or that they aren't being historically fair, and that there isn't enough opportunity to really take history into their own hands and have an appropriately ahistoric game.
because part of the fun of the Paradox games is obviously having history turning out different, and in the regard of the Asian countries, there are inherent limiters that people don't like.
What I think needs to happen is that there needs to be a way for the player to "Westernize" their country by their own means, and I say "Westernize" because that would be the parallel mechanic rather than the proposed fix having much to do with the West. First I want to address this though:
There's nothing about European culture that makes it inherently vastly superior at technological development: just look at what China was like during Europe's middle ages. It's pretty obvious that whatever the root cause of technological development in this time period is, it isn't anything inherent to a group of people.
There kind of is, and it's inherent to a group (or groups) of people, but not due to anything stupid like race. The issue is that the countries that were previously technologically superior either fell apart, lost all of their influence, adopted isolationist policies, stopped scientific investment or etc. The cultural and geopolitical climate of Europe during the time period of the EU games was ripe for Europe to steamroll technologically. The cultural and geopolitical climate for the Middle East and Asia were the exact opposite. There was a lot of infighting, a lot of civil war (yeah, there were a lot of wars in Europe, but they seemed to be very diplomatically dealt with), and lots of isolationist policies. That's why China lost all of its technological superiority. I mean, they had
reusable paper flamethrowers during the reign of Genghis Khan, not to mention all of the other neat stuff with rocketry and gunpowder. The Koreans also had very neat stuff with gunpowder. Japan didn't because they were also isolationist and kind of busy with constant civil war. So it's not just happenstance that they are technologically inferior by 14-whatever-the-game-starts-at.
However, it's totally agreeable that the player should be able to contradict history. Westernization is one method, but I think that for everyone to be happy there should be another. The alternative method would require a lot of investment and a lot of work so that it can compete with the viability of Westernization so it's not just a completely useless mechanic. Essentially, the idea is that there need to be national missions/decisions that pave the road to technological revolution and allow a non-Western-tech-group to be able to match up to the West. This will require conscious effort on the part of the nation, so that's where the national missions and decisions would come in. Monetary investment, monarch points investment in changing how things are done non-technologically (so it makes a bit of sense investing monarch points when they could just go straight into tech), trade domination (perhaps), encouraging other nearby countries to have non-isolationist policies, good relations (or more frequent, non-civil wars as war is the mother of invention), etc. It should be done in such a way that not all of them need to be accomplished, just a majority, so that it doesn't somehow become impossible, just always pretty difficult. There will also be appropriate consequences, like higher revolt chance in random coastal provinces for countries that adopt non-isolationist policies and other relevant things. Things that have some (or complete) historical support, so it's not just more BS limitations. The benefit to vanilla Westernization, then, is that you don't need to go through all this, you just let another country do it for you, basically. The benefit of this version is that you also don't need to wait for Westernization and you feel like you're really getting something done.