/ic/ - Artwork/Critique

What makes Japanese character design appealing?

Serious question; I personally find strong appeal in designs like this and gacha games market themselves almost exclusively on the characters as an incentive to spend, but everything I've read on design seems to have a differing Western approach that goes into shape design which seems more applicable to mascots rather than waifus.

Without considering shapes and practicality, and focusing purely on aesthetics - how do designers come up with this sort of stuff? Why is one character in a dress more appealing than another?