I Have said that in the redux thread, but I also find interesting to put that here:

At the final scene, I really liked Rey’s new lightsaber colour, but get frustrated to know it isn’t a double-bladed one. The biggest problem is that the Rey’s saber shot is a closed one, so we can only see one half of the saber, making it impossible to edit the other half to generate a second blade.
Rey could have a double-bladed lightsaber at the end. This is the kind of saber everyone wants to see her using since TFA and is lame that we just see it in a dark vision. If she built one new saber at the end of the movie, what if the new Rey’s saber is a double bladed one and ALSO have the “swiss army” flip function? So in the saber ignition shot, we first see the yellow blade, and after that another blade flips to upside, revealing a double bladed lightsaber that flips and is just like the Dark Rey’s one. The only differences are the colour and the stable blade instead of a crackled one.
What you guys think of the idea? I think it would be really cool, and it would also make everything more tied. Rey see a different kind of saber that fits her more (The double bladed one in the vision) so, when she built a new saber representing her new generation of Jedi will be more different than the others before, that saber will be the most different possible (in colour, in number of blades and in sense of how it works because of the flip function). I will find a time at the next week to work on that, but if you guys have some idea or tip to help I would be really very glad, and if the idea is just lame tell me either, please.