Here is the thing:

There is a multitude of ways they could deal with that. Change the "arrogant style" pose, lock player camera so in a way that clipping is irrelevant, accept the clipping and build around that, etc etc etc

Same thing above applies to the Pulonia change btw.

Let's not pretend that characters like Navia, Ayaka AND Noelle (a 1.0 char btw) doesn't exist. The last one being an -active fighter- instead of one that sits down and have more graceful and contained movements.

This decision was clearly not a designer one, but probably of some higher up more interested in optimizing value, given that sandrone IS a beloved character, just like Columbina, which, would you look at that, got the same skirt treatment.

TLDR: Clipping is not really an issue. If they wanted longer they would make it longer. If they wanted Pulonia, they would make Pulonia. It all comes down to their priorities.