Now that I don’t have a good explanation for. They’re already in production in black in Onua. And while brown could work for Obi-Wan, it really does clash on Luke and Jango.
I think it has a lot to due with contrasting/complementing colours. Red and black can look really good together. Look at Core Hunter:
What’s debatable. BIONICLE was originally branded as TECHNIC, and it used many TECHNIC parts through the years. However, many parts - while having TECHNIC-style attachment points - were extremely specific to BIONICLE’s aesthetic.
After 2003 it was stopped as being labeled under the Technic brand and then it officially became it’s own theme and themes like hero factory and chima also used technic but they are also they’re own themes as well