Ok, i know it's basically just an excuse to go around enslaving hot chicks of all pedigrees but the main quest does not really make much sense, why are Elves and Orcs both fighting for human supremacist, you could say they were mercenaries but it is clear they are loyal to the point that they are ready to die for it, so what gives. Also if you let "what's his name" escape with his sister then there should really be a continuation of some sort after that, people like that dude don't just give up, our own history has proven that violent extremists always come back to bite you in the ass sooner or later. Lenin was exiled to Syberia for 10 years and still he successfully pulled off the revolution, examples of this are endless, so after a while that guy should come back, with new army, to challenge you again.

The rewards the orcs are getting are mentioned in the story and yes, people do go along with bad guys in order to get their own rewards without seeing the large scale damage they might be doing.

Hade himself was just a tool used by greater parties. Slaver Guilds were the real force with real goals behind whole thing. 

Also Lenin didn't pulled the revolution on the Tsar, who banished him, so it's not relaly 'come back to bite you'. 

I have to admit the ending feels a bit low to an otherwise excellent climax. I don't like how your player character is just promoted to head of the Order chapter. It doesn't feel like those old dudes in the capital would really stick a still relatively new member on the head seat. I'd love to see it tweaked to where you're second in command directly under the old chancellor, who has warmed up to you a bit since you first joined and outright tells you that when he retires, he wants to place you as head, but you'll have to prove yourself. This opens things up for after main story quests where you do things for him, like investigating some desert ruins and being sent to do more complex tasks. (I mention the desert because there's an image in backgrounds called nightdesert.jpeg)