Colored gear with specific classes.

[Betelgeuzah]

The Color itself has no impact on the Stat. It is a combination of Color+Armour that determine the stats.

So what? Items are separated by the classes that can wear them. Red robe is not the same as red Haubergeon. Red Haubergeon separates GLA from MRD, while Red robe separates THM from CNJ. They fulfill their purpose perfectly. You don't mix a red haubergeon with a red robe, unless, as you said, you are mentally ill. They are completely different models, and as such can share the same color while creating class uniqueness (through the model (haubergeon wearable by "4 classes") AND through the color (red haubergeon suited for GLA)).

All classes can wear red

All classes have separate armor models which are then further divided to different colors that are suited just for them. Every class has its own theme, whether it be red haubergeon or red robe. That is class uniqueness.