Well, what the WOW texture is doing is starting with an empty texture called a texture atlas. Certain areas have been reserved for different parts of the body.
The small texture chunks are all kept on disc and loaded in to the main texture as needed.
It’s a good system for the BGE since having only one texture means you only have to do one render pass for that object. If you had 12 textures you’d need 12 materials and you’d have to render it 12 times.
Other game engines can work differently though so I’m not sure it would give any improvement there.
The drawback for the BGE is that you’d have some lag when loading the textures, also you’d probably need a different material for every character since changing the texture on a single material usually changes it on all instances of that material.
There’s also the fact that I haven’t used that function before (the shared materials problem put me off) so you’d have to find someone who has, or muddle through on your own. I also wouldn’t even know if it’s possible in Unity.
Another problem that modders have found with the WOW system is that it need to be hard coded, so if you wanted to add a tail for example, you can’t easily do that.