Goodkind is an arrogant prick and has no original thoughts.  All his books are simply soapboxes for the works of Ayn Rand.  Yet people continue to read his crap thinking it is so original.  He also claims his books aren't Fantasy but they just happen to have some fantasy elements in them blah blah blah.  Goodkind is a jackA$$.  He also has some weird rape fetish that he has to put in everyone of his books.  My guess would be that some girl broke up with him at some point and now he essentially has every female character he writes about get repeatedly raped throughout his books.  The man's got issues and his books suck.

I recall that there was a vision involving Matrim Cauthouns and Pins made out of man , as well as what sounds like gunpowder based munitions raining down on battle fields. Where was it I wonder?

That was a dream by Egwene I believe.

[ACOS: 10, Unseen Eyes, 202]

 

Mat sat on a night-shrouded hilltop, watching a grand Illuminator's display of fireworks, and suddenly his hand shot up, seized one of those bursting lights in the sky. Arrows of fire flashed from his clenched fist, and a sense of dread filled her. Men would die because of this. The world would change.

Was that what you were thinking of?

Or more likely it is this one...

[COT: 20, In the Night, 492-495]

Mat stood on a village green, playing at bowls [...] he was sharp and clear, dressed in a fine green coat and that wide-brimmed black hat [...] Rubbing the ball between his hands, he took a short run and casually rolled it across the smooth grass. All nine pins fell, scattered as if they had been kicked. Mat turned and picked up another ball, and the pins were back upright. No, there was a fresh set of pins. The old still lay where they had fallen. He hurled the ball again, a lazy underhanded bowl. And Egwene wanted to scream. The pins were not turned pieces of wood. They were men. [...] there were more new pins, new men, standing in orderly formation among the men lying sprawled on the ground as if dead. No, they were dead. Unconcerned, Mat bowled [...] Every one of those human pins had represented thousands of men. Of that she was certain. And an Illuminator was part of it [...] Still, it was only a possible future.

Basically Mat has come up with very primitive gunpowder grenades and as for the cannon...

FROM WIKIPEDIA:

Fire lances", gunpowder-propelled arrows, were used in China from at least 1132. The first documented record of artillery with gunpowder propellent used on the battlefield was on January 28, 1132 when General Han Shizhong of the Song Dynasty used escalade and Huochong to capture a city in Fujian. In 1221, cast iron bombs thrown by hand, sling, and catapult were mentioned. Somewhere around 1249, the Chinese of the Song Dynasty began to load early gunpowder in the middle of thick bamboo as a projection firearm, firing clay pellets like a shotgun.

 

Around the time of the wars between the Mongols and the Song Dynasty (1268-1279), mortars with bronze tubes first appeared.[3] (However, the earliest certain example was dated 1332). Additionally, the Chinese and Mongols took up the use of "true" gunpowder instead of the slower-burning older mixture - which made this early cannon, known as the Huochong, more reliable and powerful. During wartime, the Chinese used the early gunpowder weapons in defence against the Mongols, mounting more than 3,000 bronze and iron casted cannons on the Great Wall of China. The weapon was later taken up by the Mongol conquerors, and also the Koreans. Many of the earliest weapons seem to primarily have functioned as psychological weapons, a trait gunpowder arms would keep for a long time.

 

From the early 14th century Chinese manuscript known as the Huo Long Jing, a passage refers to the first use of cast iron shell casings for gunpowder-filled cannon balls, fired by what the Chinese had termed the 'flying-cloud thunderclap eruptor' (fei yun pi-li pao):

 

The shells (phao) are made of cast iron, as large as a bowl and shaped like a ball. Inside they contain half a pound of 'magic' gunpowder (shen huo). They are sent flying towards the enemy camp from an eruptor (mu phao); and when they get there a sound like a thunder-clap is heard, and flashes of light appear. If ten of these shells are fired successfully into the enemy camp, the whole place will be set ablaze...[4]

Having an illuminator who is knowledgable of gunpowder ratios, Mat should be able to skip the firearm evolution process directly to high explosive powder for artillery with a fairly decent range.  Also, Mat would likely use explosive shells (having seen their effectiveness with the Dragon eggs) and stay away from solid shot.  I would predict a fairly quick evolution to the bronze cannons of the 16th/17th centuries known for excellent reliability, accuracy (when the crew is properly trained...no easy task) and durability (bronze is much more resistant to stress than cannons made of iron...problem is it costs 8-10 times as much)

Similar to the Roman pilum, since they were able to carry 3 or 4 at a time. 

Other than the length, the Aiel spear is most certainly not a pilum or even similar since it can be reused.  Pilum were specifically designed to penetrate a shield, get caught with the barbed tip and bend so as to make both the shield and pilum useless after one throw.  Aiel spears are much like Zulu spears (as mentioned above) though.  Essentially it is simply a standard spear with a shorter staff and then wielded by an expert fighter.