I explicitly said "excluding anything from LotV" and you literally cite something from LotV. This is now the third time I've explicitly and specifically excluded the events from Legacy of the Void because I think the writing did take a nosedive there for reasons that were unrelated to the story itself.
I don't see anything strange from a narrative perspective with Diablo taking on a more slender and feminine form for the Prime Evil Diablo. Baal and Mephisto were both much more slender than Diablo, and Leah (the vessel) is female.
Your first point isn't something I ever argued against, and your second point has no apparent relevance to the writing.