TCW and the nuEU have more-or-less adopted yellow as a less common third colour for Jedi lightsabers, so seeing Rey with a yellow lightsaber wouldn’t be all that impressive for me. And Mace Windu had his purple lightsaber, so likewise it wouldn’t be very impressive to me to see Rey with that colour either.
I’d like to see her with a teal or orange lightsaber – both lightsaber colours no character in the new canon has used thus far.
Actually one of the siths in the SW fanfilm Contract of Evil had a orange lightsaber so that has already been done(although it was admittedly a none profit kind of fanfiction unlike the EU).