I just quick read this thread. I read every post, but maybe jumped some paragraphs. I am sure that some points are already mentioned, please forgive. Another problem i have is that i dont know what parameters of the economy are there that are changeable without coding. If I violate the "no-code-change-rule", please forgive. I try to keep the proposed changes small. But first some toughts at the situation.
First:
Again there is a discussion about PLers vs RPers. To be honest, the economy offers a system where you are rewarded for doing several things in a different grade. Thats similar to real live. PLers try to find the easiest method to gain largest amounts of tria as fast as possible. People do this in real life all the day. I see nothing bad with it. If you lower platinum to fix that, then the PLers will switch to another activity and mine gold for example. To aviod that PLers cluster on a certin activity, you must switch off all sources of income. Bad idea imho. Oh, and by the way, I never have seen someone in real live insisting to get a lower paid job in a capital because the live should be in a capital. So from a certain point of view the PLers make a realistic roleplay. I don't think that lowering the platinum will make people better role players. Heck, there isn't even an agreement on what a good roleplayer is. Enforcing roleplay through the economy seems like a bad idea to me.
Second:
As I have read the thread I got the impression that there are many ideas how the economy should work. Some think of it as a way to enforce roleplay, others want to get tria fast to be able to powerlevel. Maybe a discussion about the goals, what the adjustment to the economy should trigger is necessary? I think a goal should be to offer a way to earn tria that is entertaining. After all this is a game and games are supposed to be entertaining.
Third:
In this thread i heard opinions that the platinum triggers an inflation. At the same time many crafters complain in game about an deflation. I can remember that the prices for crafted weapons once where really high and now they are much lower. I don't see any inflation. When many people concentrated on crafting, many crafters where around and today the weapon market is saturated. If for example, you would implement armor making and sell those to other players for a high price that will work out for some time. But many players will become an armor crafter and we would get a similar situation as with the swords today. I think the problem here is that weapons wear of far to slowly.
The REAL problem:
There are many different kind of players with different opinions about how the economy should work. Well, I think there is no solution to that problem, as even there is no common point of view what the problem actually is.
There is an deflation, it is to easy, it is to hard, hyldaa is too deserted, the mine is to crowded, there are to less roleplayers, there is an inflation, too many tria in game, its too hard to earn tria.

Thats my impression what is seen as problems. Different player, different opinions. How to fix that?

Maybe the question should be if its too boring or "too entertaining"? I think the economy can't be easily fixed but it can be made more entertaining. Only mining is a bit monotonic. In earlier times people digged gold ores at the mage shop and sold that to Harnquist. Then the possibility to smelt the gold and sell ingots and stocks was added. That was one change that i liked as that made the players interact a bit more. But this "chain" stops at ingots or stocks because higher refined goods are less valuable.
So far we have chains of goods like: XYZ ore -> XYZ ingot/stock.
What I dislike at the current economy:
There are certain goods that bring less tria then the resources put into it. If you craft a golden shield you put in resources with a value of at least 18k into it. And you receive an item beeing worth less then 8k. Thats just one example but I think there are more items whose value is lower then the value of all resources used to make this item.
Now lets imagine what would happen if the price for a gold shield would be insane high. Maybe 25k? Shield crafters would craft shields to make tria. Soon they would run out of steel and gold and pay more for those resources then the npcs do. In the long run some people would switch from mining to crafting of shields and there would be less miners. And the miners would be more diversified as there is need for iron, steel and coal. I would consider this an improvement.
Suggestion for a short term improvement:Adjust the npc prices for items in a way that its more rewarding to make more advanced items. Make it for players less intresting to sell stocks and ingots. Make it interesting to sell swords, axes, shields and other higher developed items. IMHO the problem is that the lower developed items like stocks are the most rewarding. This prevents any economy to develop.
And for the sake of the crafters, make things to wear out faster. For example if someone buys a pair of quality 300 short swords today, he has great weapons for many many hours of in game time. Maybe half a year of ooc time even if he plays a lot. As a raw guess is just state that each month less then 50 pairs of weapons wear out. Thats to less IMHO.
Suggestion in the long run (surely need code change and more art):Make it possible to craft advanced items and make it rewarding. People will try to get tria as fast as possible and if that means they have to work together to make a long chain of production steps this might actually happen. Bring other resources like wood in game and make the things that are craftable so large in number that a single player never can make it all and never can get the overview and never can max out in all professions. Shield making, Axe making, Armor making, Tool making, Food making (aka cooking), potion making(aka alchemy), Brewing, bakery, butchers, tanners and so on. At lower levels they can only produce low paid goods, at higher levels they can make more interesting goods.
Thats just an raw idea, but imho planeshifts direction of the economy should head there. I could bable around here for more changes but I will stop now. But I think there is some potential with the given code and art by just making higher developed items more valuable.