Ah, an excellent question!
A fantasy world, which is a kind or subset of invented world or secondary world, is very much like the primary world in its basic structure and form. The geopoet or worldbuilder will consider numerous factors in making her world and you will see many parallels between the work of the worldbuilder and the primary world itself.
UPPER LEVEL PILLARS
You have already highlighted several upper level pillars of worldbuilding. The clerestory, if you will:
Other high level pillars are basics with respect to sophont beings:
- social structure
LOWER LEVEL PILLARS
But beneath these high level ideas are more basic ones upon which those are built. In the primary world, we view these more in terms of basic physical sciences.
- Anatomy & Physiology
But there are layers of pillars yet lower down! These are the ideals that the geopoet wishes to convey through the medium of the artistically conceived world. These are the fundamentals upon which the secondary world itself is built.
- What kind of world is this to be? What is the basic perception I wish for others to see as regards my work?
- How similar or different is this world to be from known models (i.e., the primary world)?
- Is this to be a world of stable & rational Law or is it to be a more chaotic and Lawless place?
- What fundamental Laws of Reality shall be established?
- What powers do these Laws confer on the inhabitants of this world?
Notice that it is the answers to these questions through which the geopoet will set the tone for all further worldbuilding work. For example, if I choose "more chaotic but not entirely Lawless", this allows me to envision a secondary world where natural laws and sciences exist, but those laws do not necessarily hold constant everywhere & everywhen. Loopholes may exist; the very fabric of reality may be stronger or weaker by location.
I don't know much about Warcraft, but I do know some things about Tolkien's concept of Middle Earth. From the bottom up, his conception is very much a world of stable & rational Law, very similar (in fact, identical to) the primary world, but with the aesthetic of a mythical age.
Moving up, Tolkien takes into account all the basic sciences. When things happen, they happen with reason and follow normal models of cause & effect & consequence.
At the top of the heap, we can see clear evidence of his consideration of the long history of Middle Earth, its languages, cultures, social structures and so forth.