Having the lightsabres monochrome, or only two colours, works if we are keeping the Jedi the morally questionable force that they are in the official prequels. If an edit is trying to make them more clearly good, it makes sense to give them different colours — it'd be difficult to pull off, but in this scenario I'd be in favour of every Jedi having a different colour, whether it be just varying hues of blue and green or running the gamut from yellow to purple. I don't think that'd be any harder on the eyes than a sea of blue or blue/green, and it ties in with the idea that Jedi all make their own sabres.