I think in principle, adherents to the Light Side of the Force are supposed to weild blue lightsabers (as it seems to be an archetypal colour of virtue and goodness), and adherents to the Dark Side weild red lightsabers (as a symbol of aggression and passion).

So that's the colour issue. I think that the definition and richness of the lightsabers in the PT kind of detracts from the mysticism of the lightsaber. Lightsabers should look a little ethereal and mystical, but solid enough to look as though it will have an impact on the physical world.

I hope that was vague enough for ya.