the answer is simple.
azeroth's version of r'lyeh.
http://en.wikipedia.org/wiki/R%27lyeh
sure nzoth might be a huge bad guy old god that lives under nazjatar and the maelstrom, but if the ulduar globes can be trusted, there is still a large mass of ocean on the opposite side of the globe.
lovecraft's site of r'yleh is quite near the oceanic point of inaccessibility, where there is no major land within a huge area. seems pretty similar to the ulduar globe.
lovecraft on cthulhu
from the puzzle box of yogg saron
n'zoth is the presumed speculation of who is in ny'alotha, the city referenced in the puzzle box of yogg saron, but what if that is not the case.
if nzoth is in nazjatar, and nazjatar is not ny'alotha, then what is?
before the sundering, azeroth was one enormous continent with the well of eternity in the center, and zin-azshari was on its shores. during the sundering, zin-azshari sunk as a whole damaged landmass into the seas. after azshara accepted the old gods help, transforming the highbourne into naga, they built nazjatar. it can be a safe assumption that nazjatar was built around and in old zin-azshari. both are close the the well of eternity/the rift
so there is an old god near the rift, and it is most likely nzoth, however, the well of eternity was not always underwater, so the old god underneath the well wasnt always underwater. moreso importantly, when the titans chose the well of eternity for its location and its power, why would they build it on top of an old god? did they know of the old gods at the time? was the well used as a prison?
ny'alotha is similar to nylarthotep, a figure in lovecraft mythos. since blizzard uses lots of lovecraft mythos charachter names as inspirations, ill elaborate on nylarthotep. nylarthotep is known as the crawling chaos, and the god of a thousand forms. his father is azathoth(azeroth), and one of his siblings are
the nameless mist. nylarthotep is known as a great deceiver and walks the word of men in the guise of a tall, slim and joyous man. he has thousands of other forms and most of them are horrifying. he cultivates followers and uses propoganda to achieve his desires. he has a mocking contempt for his masters. this sounds very familiar to me.
wrathion.
one of my speculations that ive posted before is wrathion was always evil. he is using us (the players) as followers and is using propoganda to achieve his goals. he wishes the sha, and all of their followers to be destroyed. he wants a united army to be ready to stand against the legion.
now azathoth is the supreme grandfather of the lovecraftian gods. in a family tree that lovecraft explained, he was the direct progenitor of all of the gods. his children, nylarthotep, the nameless mists and the darkness. his 7 known best offspring are yog-sothoth, shub-niggurath, nug and yeb, wilbur whateley, cthulhu and tsathooggua.
a common speculation has been that there are 5 old gods, and each location of the old god draws out a pentagram. this is a cool assumption, but has been proven false and also does not fall into lovecraftian similarities.
the known old gods are now cthun, yogg saron, nzoth and yshaarj. yshaarj's body was destroyed by the titans and formed the 7 sha.
puzzle box
the 7th sha was recently revealed as the sha of pride, which 'created the mists'. shaohao conquered all of the sha, his negative emotions, except his pride. shaohao says "that pride is good, and it is bad. more dangerous than all the others combined." "only by working together, can we overcome the
darkness, all that stands in our way is pride" this new information reveals that the pandaren, through shaohao are inherently vessels of the old god's power.
so ive gotten pretty far off course from my original statement of that azeroth's ry'leh is on the opposite side of the maelstrom. but taking into account the vast similarities and inspirations blizzard takes from lovecraft mythos, there are a lot of correlations. so ill simplify them.
azeroth-azathoth. the supreme old god.
wrathion-nylarthotep. the great deceiver, seeks to undermine his elders for his own agenda.
7 sha-birthed of yshaarj when his body was destroyed. latched onto the pandaren people. purged by shaohao, except for the final sha, pride.
the puzzle box of yogg saron-as cryptic as it is insightful. i see this as the works of lovecraft, adapted to fit WoW.
there are 7 old gods. we know of 4. 3 remain unknown. one has been speculated to be underneath tirisfal glades.
the massive oceanic expanse opposite the maelstrom on azeroth is home to unknown power. it holds no travel routes, and is not known to be traversed. thats a very big area of potential use.