It was rather sad for me to read the descriptions of clothes in the "Sylvanas" novel. It's not fault of the novel itself, it's just I've been making head canons of a couple of things since 2010, and now I'm "kinda upset" that no one shares my thoughts.
I mean, imagine that the noble houses of Quel'Thalas, who are members of the Convocation, shares certain colors among themselves. House of Windrunner wears brown(?) and gold (maybe something similar to what Zhongli from Genshin Impact wears). Sunstriders appears everywhere only in red and gold. House of Salonar only wears blue and purple, for example, etc.
Imagine that clothing emphasizes status and indicates to which House a certain characters belongs and whose values they shares.