Just my two cent, is union between orcs and humans feel earned? I think orc story arcs could be a lot better with some expansion.
Orcs of arkain heavily mirror that of Warcraft. But at least in warcraft, orcs 'repent' by finally cooperating with human, night elves in pushing back scourge/ demons at mt.hyjal. But while arkain orcs talked about changing the old way, they don't really 'redeem' themselves. Their arc mostly involve invading Salria, which is frankly overthrowing its 'rightful' rulers. Not to mention bringing large population of non-humans to Salria will potentially displace local population. Salrian humans are pretty much subjugated and forced to accept orc's rule whether they like it or not.
Like i said, tribal dominion contributed nothing in pushing back the common enemy , the demons. At least in second orc story book, they helped fight against demon legions. So their 'redemption' story does not feel earned.
Or maybe Shar do not include 'redemption' story because he never intend tribal dominions to be 'kind-hearted noble savages' like blizzard regarded to the Horde?
They dont seem like warcraft orcs to me though, sure Hord and Dominion have the similarity of being two factions that are made up of different races but other than that, the similarities between Arkain Orcs and Warcraft Orcs are superficial at best.
In regards to overthrowing the rightful rulers ehh its not like the Orcs were gifted the land, they conquerd it and then they managed to defend it from the Undead invasion so they kinda earned the right to be called the rulers of that land.
Salrian humans aren't really subjugated they have the right to join the army ( subjugated people usually are not allowed to serve in the millitary/bear arms), they were given the right to choose between leaving the lands or staying on them (subjugated people are usually either expelled, genocided or put into slavery ) i guess just like any other race within the dominion they have their own portion of the lands, their repersentatives and their own religion (i doubt the humans follow the shadocracy theology, they most likely stick to their light worship)
The way i see it with the whole Salrian debacle, it was a upper managment change, from what i remember from the stories the commoners and their ruling elite didnt see eye to eye in most things, your everyday commoner in salria had no issue trading with the Centaurs (also native to Salria) it was the nobility that tried to enfore a no contact policy and went to war with the horsemen. Out of all the kingdoms Salrians would be the most likely to actually go along just fine with the Orcs since they were never really raided by orcs, they had no trouble co-existing for a long time with centaur so to them being ruled by an orc isn't really that much of a big deal, they still get to be mercenaries, they still have the right to own land and they still have repersentatives Vanessa is the main repersentative (a human raised by orcs) but i would assume there are other Humans who also hold a degree of power within the new Dominion structure, Shar can clear that up for all of us.
On the topic of arkain Orcs being similar to any other fantasy orcs, i actually cant find another similarity between them, with warcraft orcs they are similiar on a surface level, LOTR orcs have nothing in common with arkain orcs, Warhammer orcs are totally different from arkain orcs and other fantasy orcs (both 40k and fantasy), Armies of exigo orcs are also different from arakin orcs. Maybe some rpg orcs might be similar to arkain orcs but no rpg game that has orcs similar to arkain orcs comes to mind (maybe baldur's gate orcs BUT that is a strech)