how it started:

Blue for good guys and red for bad guys.

Luke insert the green one.

We have dark forces 2 that shows the bad guys have rainbow sabers not only red.

then as an oficial cannon lucas make windu with purple.

then KOTOR defines the colors to classes and shit.

LESS IS MORE RIGHT? we never see a dialogue like: hey dude nice yellow saber you have! are you a sentinel?

EU details are useless and they work perfectly to comics and novels.

Im not saying not having more colors to the edits. After there is free will :) but i like to think it like its star wars. Real star wars. not with many parameters or knights, masters, sentinels, neos and smiths.

-Angel