As you all know at the moment we are drowned with new images and information about orcs, goblins and other evil creatures of The Hobbit trilogy. And the more we learn about them the merrier I start to compare them to the ones of the Lord of the Rings trilogy. In an interview with someone Peter Jackson told us that now he's doing three films he's able to tell us more about "The Rise of the Necromancer". Here is my theory how we gonna notice it while watching the AUJ, DOS and TABA without seeing much of Sauron himself. Let's compare some of the evil races of AUJ to their counterparts of LOTR:

Goblins of AUJ:
No armor (loincloth), no heavy weapons (whips, wooden spears, knives). Obviously they're living in their own civilization [Goblin Town] with their own ruler [Great Goblin]. Very independant if you ask me. And everything looks hastily cobbled together. No wizard or Dark Lord behind them.
Goblins of LOTR:
Uniform armor, forged weapons and armor (shields, chainmail, helmets, swords...). They're in Moria because they were sent there to destroy the dwarven realm of Khazad-dûm by Sauron.
-----
Orcs of AUJ:
Fimbul, Bolg and Yazneg are serving Sauron but are wearing skin or bones as their armor rather than chainmails, corslets or forged things. Perhaps Sauron wasn't able to rebuild his industries and forges yet? Everything looks very savage. Although they serve Sauron it seems that they're also fighting their personal conflicts (Azog-Thorin-Dain-Bolg). It seems that they still have a bit of their free mind left.
Orcs of LOTR:
Orcs of Mordor and Isengard are wearing heavy armor and weapons forged in their own industries. Orcs and Uruk-Hai look more improved, more disciplined (for orc standards) and every orc follows only one goal: To destroy the world of Men, Elves and all the Free People on behalf of their master. No real sign of an own mind.
-----
Wargs of AUJ:
They're looking more like animals and independant beasts than bred creatures. They're looking like allies but not servants. Also they seem to have their own primitive language and a kind of "society" with a leader [white She-Wolf].
Wargs of LOTR:
They're looking more like bred war maschines than animals. More improved, stronger and obedient. Following the orders of Sauron and Saruman.
-----
Trolls of AUJ:
They've got names, they've got the ability to speak and they seem to be independant too. They're living their own lifes and are not serving anybody. They kill if they're hungry and not on behalf of a dark lord.
Trolls of LOTR:
Obedient and improved bred elite-warriors in Saurons armies. No own mind, no speaking. Armoured and ready to fight everybody who stands against their master.
-----
All in all: I think we gonna see how all of these evil races are losing their independence during The Hobbit trilogy one by one. Perhaps we see what Saruman tells Gandalf in FOTR: "He is gathering all evil to him. Very soon he will summon an army great enough to launch an assault upon Middle earth". I think that's how we're going to notice "The Rise of the Necromancer" while watching The Hobbit trilogy without seeing much of Sauron himself. We will see the development of his servants and their loss of independence. Sauron would be still more the incarnation of evil and growing darkness than an actual single person. But that's just a theory.