I've always wanted to see a white lightsaber blade in SW, and I'm hoping that if Rey makes her own lightsaber in 9 that it'll be white. Then Luke can wield his green and Anakin's blue simultaneously . Kidding. Luke would probably stick with his green and perhaps Anakin's becomes like excalibur and always gets passed down to the next "star pupil" of the new Jedi...
Never really delved into SW Legacy but I quite liked the white lightsaber's of the Imperial Knights. Heck, I like the concept of them and hope it's one of the things Disney chooses to cherry-pick from Legends.
I'm cool with any color other than red, adding white or other colors is fine but if they stick with blue and green I'm cool with that too.
I remember when Luke first ignited his new green sabre in ROTJ, I remember thinking "Holy Crap! GREEN! How cool is that!" The green made a statement, especially when combined in that film with the 'Jedi Luke' personality of that film, and the ethos revealed in how he behaved on Endor. Green was a statement in that film. Whatever they do, I hope they reveal new colors slowly, and at pivotal emotional reveal moments. My vote would be GOLD.