Imaro
Legend
No. I don't need to for the Great Wheel, do I? That's in every planar material regarding D&D 3. As I said, maybe the AD&D Planescape material would change my opinion on the quality of the Great Wheel. But this is just "potential quality" to me, unlike the 4E cosmology, which I read in played in and definitely like.
I was moreso referring to the comments about Planescape and The Lady of Pain. But no, you don't need knowledge of Planescape to discuss the great Wheel.