I hadn't seen anyone on here discussing this yet.
The Broker has the following quote in the new book:
The fact that he decoded any of the glyphs at all was more progress than has been made in many ages of study (though whether "zereth" is best translated as "keystone" or "cornerstone" remains a subtle, yet ongoing, debate).
What are the implications you can think of?
Couple of quick definitions:
Keystone - a central stone at the summit of an arch, locking the whole together.
Cornerstone -(1)an important quality or feature on which a particular thing depends or is based.
(2)a stone that forms the base of a corner of a building, joining two walls.
So one way to translate Azeroth would make it the central stone, locking everything else in place. The other makes it either an important feature or the base of a corner.
It seems to me, the Keystone makes Azeroth unique, where as a Cornerstone would presumably have at least 3 other Cornerstones and join 2 things together.