The WTO recently came to an agreement on the standardization of international trade documents for clearing customs. It took 15 years for this piece of minor improvement in trade activity to be adopted.
The WTO is a brilliant solution to solve the previous malaise of trade agreements. Before the WTO every country was subject to the pressure of its own most powerful export lobbyists. Countries were often in open hostility caused by pressure from their export lobbyists. At the State Department level there was great acrimony and a general sense that trade, while desirable, resulted in horrible country to country relations.
The WTO solved that problem. Any nation that wished to complain about protective barriers around another nation could use the WTO. If the other nation lost two cases on the matter before WTO judges, the complaining nation facing import barriers was allowed to create temporary barriers up to an amount equal to the money lost before the WTO judgement. In other words the WTO allows trade revenge after a court finding that the original trade barriers had inflicted costs that warranted the trade revenge.
The system worked perfectly for a decade until two kinds of countries were allowed into the WTO. It still works for most large trading nations.
The wrong kind of nations were allowed into the WTO despite the fact the WTO requires unanimity in all decisions. The countries being allowed in were not effectively subject to WTO sanctions.
The first cluster of countries allowed into the WTO, mistakenly, were the export-invulnerable countries. That included countries like Saudi Arabia and Russia that only exported oil and could not be subject to retaliation for import barriers. If one country retaliated by not buying oil from Saudi Arabia it wouldn't matter. Other countries would buy the oil.
Consequently there was no way this kind of export-invulnerable country could be punished by the WTO process.
The second cluster of mistakenly admitted countries are known as ALBA (Cuba, Venezuela, Bolivia and Nicaragua). These are communist nations or nearly communist nations that have no real reason to be in the WTO because they are not significant traders. They don't even comprehend the reason the WTO exists. They just wanted to join because they consider their exclusion as a priori proof that the world is unjust.
I have no idea why any of the countries in either the first or second cluster were allowed to join the WTO. I'm sure they used political influence on other nations to include them.
Certainly Saudi Arabia could manipulate many smaller countries to force its inclusion in the WTO membership. Once countries like Mexico and Guatemala became members of the WTO they could be manipulated to include Cuba and Venezuela.
We should not expect any improvements in the future world trade agreements because of the WTO. Nevertheless its current function among major trading, countries remains important.
Fortunately other major trade agreements are underway.