Please take this only as free thinking gothic-3 ideology....for open discussive purposes and not conclusive.
The short answer has to be yes - 'A-on-S' is a pre-requisite for the world redemption conclusion, the main core of the game (the raging war of the gods) and cannot be dismissed. I think it relates to the three areas seperately, Myrtana, Nordmar and Varant, meaning each can be dealt with on a seperate basis per the gods, Innos, Beliar and Adanos.
According to the books (see eternal wanderer) there is a 'way' or sequence per a previous historical account. It suggests that there need be no killing ("put aside your staff") etc' which is confirmed by the dialogue from Runak the highest of the druids when he says the fate of the world is in your hands using the magic power of Adanos (via the druid stones etc'). However, just to complicate things a little, the orcs in the Nordmar are hostile and can be killed by the 'natives' of that land (with a gentle push from nameless who is the present day 'wanderer') .....this suggests Adanos magics.
So when Adanos (per the books) says "nevermore shall you set foot in my land" it means free from opposing factions? concluding that the orcs in Mrytana and Varant need not be killed but the situation be rectified (per Beliar) from those lands.
By the way Runak also confirms that "the beast" is in fact "the orcs" (per the books - "and the beast was hunting him")