Okay I don't under the whole concept of Orc army control for shadows of Mordor. The only thing I really took away from the trailers I saw is that certain NPC attributes are randomly generated making each encounter/play through unique. What is the deal with Orc armies?
There's quite a bit going on with the armies.
1) Nemesis system is Orc learning your fighting traits. And remember and reflecting that later. So in the example they had during one fight the hero fought a bunch of Orcs. He threw one in the fire and then that burnt Orc ran away. Later that Orc climbs his hierarchy later and becomes a boss/boss fight. Burnt face and all.
2) You can choose to kill a boss or turn him into your henchman. If you turn him to your side you also get his followers. Later in the game you can have your factions fight other Orc factions. You can also used that turned boss to do attack other bosses at certain points.
3) You can turn a low ranked solider so they start fighting for you. I'm not sure if they continue to climb the ranking ladder if they survive.
4) I don't believe that at any point you actually take manual control of an Orc.
5) I'm unclear on this but you can grow your reputation to make others (Orcs) fear you. I'm not sure how this impacts the game.