What is really said about N'zoth is that as the last surviving & weakest Old God he chooses to remain hidden in the lower depths of Azeroth seeking to corrupt nobels of Azeroth. This means he is bending the powers of the prime Sha to his will. But what one has to ask is how this will be affected by the magical power of Gorshalach (the sword of Sargeras and the mysterious powers it has unleashed into azeroth still under study by the council and the cenarion circle)... there is no doubt N'zoth will rise but as the weakest Old God does he really present a challenge to Azeroth? or once awakened rather than succumb to it's natural devouring tendencies through centuries of plotting & scheming & hidden animosity will it seek vengeance on Azerothian heroes and the Titans and try to unleash the greatest threat of all to end Azeroth = Y'shaarj. Question and answer is up in the air... but, I can't see them unleashing N'zoth without reanimating & unleashing a Y'shaarj eventually also; as these are the 2 known Old Gods Azeroth has yet to face. I can't see them not creating a raid or 2 without both of them in it! & it's likely Y'shaarj will be an excuse to create the hardest, most epic hair pulling raid ever! Kind of like C'thun was. But N'zoth was confirmed weaker than even C'thun which is why he was imprisoned in the depths first.