>>56835736I can answer that with simple logistics
X/Y, nearly everyone who wasn't the player character and some select characters got 1:1 models.Getting "billboards" of 2D artwork was the best you'd get for most characters. The only offset for this was if they'd appear in the anime to make the difference and not many US fans tuned in to the Pokemon anime past a certain point of their childhood.
SW/SH, there were no chibis. You had full character models being as expressive as possible, dynamic close-ups and what not. You can pull up video footage from SWSH to see characters like Melony interact with the player or what kind of expression they make dynamaxing or how they react in battle and get a good idea of their mannerisms. I doubt it would've been the same effect if SWSH had XY's production values.
Long and short of it is Drasna's representation was too abstract by comparison.
