[quote=Sep]
Oh my god...So much gammeeeee. Colours weren't defined by classes, and there weren't actual classes in the Jedi Order that's just something to make it easier for games q_Q. Sorry it's just a bit the games brought forward that annoys me.
[/quote]

I think it was an old republic thing because in war you need to distinguish your warriors from your diplomats/scientists and your specialists/intelligence. Later all jedi could study whatever they wanted to and it didn't matter, plus only blue and grenn crystals were common anymore.