The “all the bad guys- and only the bad guys- have red lightsabers” is a prequelism I can do without.
It’s not a prequelism. The reason Darth had a red saber in Star Wars was to create the simple contrast of good and evil, just like everything else in the film. He also wore black. Do you want Kylo to wear something else just to emphasize the unnecessary points of originality? Just because something is “cliche” doesn’t mean it won’t fit.