The Ongoing Issue with Xaela Scale Coloration

[Raikai]

Maybe the rework they did/are doing to the character creator structure may allow the player to choose different scale colors. Even if still stands in the range of light tones = Raen, dark tones = Xaela.

[Oizen]

I wouldn't read too much into it, it's probably just down to how the textures interact with the skin colour.

Because the scales on Au Ra aren't some kind of addition to your body, that would lead to all kinds of clipping issues.
They are painted onto the normal skin texture and then made to look like they "stick out" with normal maps.

This is also what makes it a lot harder to just slap a selection of multiple colours into the game. The colour of your scales is painted on that way, so that's simply the colour you get.
The scales of Raen and Xaela aren't just some guy moving a colour slider, they are two different sets of textures (Raen additionally also have a much paler base skin tone than any other race).

There is, as of right now, no system in the game that just swaps textures on the fly.
When you see a recolor of a mount for example, or one that shares a model but has vastly different textures, that is an entirely separate entry.

So if you wanted differently coloured scales right now they would probably just have to add new sub-races with different textures.

It wouldn't be that hard to do seeing as we already have an entire system for applying different colors to an object in the game with multi-dyes. Average Items themselves in the game actually have up to 16 dye channels regularly, so enabling two of them for the body is well within the abilities of the game engine.

The problem becomes if the devs want to sit down actually do that. We just got confirmation of horns being decoupled from the head so I wouldn't expect anything else yet. Maybe some day.

[Absurdity]

It wouldn't be that hard to do seeing as we already have an entire system for applying different colors to an object in the game with multi-dyes. Average Items themselves in the game actually have up to 16 dye channels regularly, so enabling two of them for the body is well within the abilities of the game engine.

It's not that simple.
Skin textures use a different shader than gear and monsters do, one that uses the data within the textures for different purposes and consequently achieves a different look. They don't have dye channels, or even colorset files for that matter.
I'm not knowledgeable enough about the technical aspect to tell you exactly how they differ, but you can see it just from looking at the textures themselves.
The skin shader lacks the index map that all gear uses since 7.0, and instead of a colorset file it uses a diffuse map to get it's base skin color.