It partly plays on thier caste system and the story built around them. The following based on the manual and caste descriptions.
Orcs who lived on the steppes and plains (contending in effect, with humans for pasturage and water rights,) became the mighty Uruks. Thier size and strength served them well against the light cavalry of early man, and the fact they consider themselves warriors first shows how deeply that mentality has been ingrained in them. Uruks who've lost thier clan to conflict or other calamity become wandering warriors known as Ronin, joining clans willing to house and feed them for thier skills at arms. Along with some of the best orcish weaponry and the orcs best-suited to battle, we get a general mongol/east asian vibe.
Orcs who lived in the forests and jungles had to fight the elves, generally by turning the forests against them. This gives us the majority of the dreamwalker castes save for the basic and sorcerer varieties who were probably a regular fixture in any clan as spiritual leaders and the leaders of mountain clans according to the manual, respectively. Forest orcs give us the aztec themed stuff, and most likely many of the early-game warcrafter stuff.
Orcs who lived in the mountains tended to live like dwarves, delving deeply to pull up materials to make what they needed and producing it in vast quantities in thier inefficient (but effective,) smoke-belching foundries, being lead by Sorcerers. Some interbred with trolls, also giving us the Ologs. From these fellows we get stuff like the blacksmoke furnace and orcish factories, and can probably attribute flechette guns to them as well.
Corsairs were the sea clans, and made war by ship, and thier learning rates and such with firearms and trade make it abundantly clear what they did - raiding the coasts where man and elf often settled. From these orcs we have the often highly effective ship-based raiding and general mastery of guns amongst orcs.
Artisans, Common Orcs, and Snaga most likely made up the rank and file for most clans off the grasslands, just as they do now. Storywise, Snaga in particular are held in contempt by the Uruks/Ronin because they're so ill-suited for facing the enemy head on, being small, cowardly, and weak compared to baseline orcs - just like the goblins they unfortunately have ancestry from. Artisans are simply common orcs who've learned traditional methods of crafting everything from weapons to toys, while Snaga probably result from the numerous goblins who probably followed orcish clans into battle - either out of respect or coercion.
Skip ahead to the times of the mod, the time of writing and recorded history, and things have changed. Humans developed better guns and heavy armor to mow down charging uruks and weather thier slashing blades and displaced them from the grasslands of the world, and thier superior cannons allowed them to combat orcish pirates more effectively, driving the Corsairs from thier coastal clanholds.
The elves learned how to extract mithril from the ground via thier plants and learned the ways of the animal, allowing them to drive the forest clans from the forests and jungles with packs of predatory animals both mundane and fantastic and rains of mithril arrows and the flash of shimmering spear and sword. The forest clans, armed only with the primitive likes of blowguns, simple bows, claws and raking swords (tools ill-suited to punching through mithril armor,) fought viciously and to some, valiantly, but in the end stood no chance against the better-equipped and supported elves.
The dwarves, gnomes, and humans, unwilling to share the riches of the mountains, fearing for thier safety, and not desiring to let enemy strongholds stand, lashed out at the mountain clans, and much like dwarven fortresses elsewhere they fell one by one. With their sorcerer-kings and many of thier fellow orcs defiant to the end - up against dwarven steel, gnomish machines, and human cannons - thier defeat was inevitable.
Succubi, Warlocks, and Kobolds meanwhile simply saw them as an ugly foe to practice the art of war against, as walking bags of resources, and either safety or a place to steal shiny things from respectively. The orcs ignored the latter, while the former two were met with the same enthusiasm as any other enemy.
In wake of this, the shattered clans of steppe, mountain, sea, and forest are forced to gather thier remaining numbers and wits in the only place few have interest in - the frigid tundras and taigas of the world. From this amalgam of differing clan cultures we get the taiga clans, which also means they fit just about any playstyle - From digging into mountains and trapping it up like dwarves or gnomes, shieldwalls backed by hordes of archers defending massive herds while the orcs shelter in simple homes in the soil like kobolds, or surface cities that always meet the enemy head on with blades, magic, and bullets and anything else - far more readily than any other race besides perhaps dwarves.
This also results in orcs being of many different stripes for story-making purposes, since one hold might be based around building a stone city while another is centered on rediculously large cattle herds, and another is trying to recreate the old mountain strongholds, and Uruks and Dreamwalkers may speak and write differently to Snaga or Olog as an example for telling those stories.
While they could do with some streamlining and modifying many society arms kits, thier general feel already fits extremely well: a race that's only just getting back on its feet after possibly decades of getting thier shit pushed in by the peoples they used to be able to bully at will. They do fit more offensively-minded players though (thanks to skill rate and size bonuses,) and may need to have thier raiding dropped since it doesn't seem like it'd work right in the newer versions. Of course I'd support them trying to force others to see the world as they do now, making for an excellent snatcher race that has an actual reason to kidnap people - raise them as orcs, so they may truly know the suffering the "civilized" peoples have inflicted upon them.