The biggest and "heftiest" (in my opinion) addition to this skin isn't just the multiple skins the player can use but also the countless multitude of Voiceovers that coincide with the skin chosen. IT"S NICE! Admittedly, some friends and I wished she could change skins at will (like Sona's) and all of us pretty much called her "walking chroma skin Lux at first until we used her." The sheer multitude of voiceovers and particle fx can justify the "Ultimate" title. The experience for each game if you can take the time to listen to her Voiceovers and interactions is pretty incredible.
https://www.youtube.com/watch?v=K-q8aYMOzUY
Imagine personal moments of satisfaction killing Janna in Wind or Storm form, Nami in Water, Brand in Fire or Magma form, Arclight skins in base Light form, Ivern or Elderwood champs in Nature form, frost themed champs in Frost form, or Darkstar skin champs in Dark elemental form, or even using opposite elements for more role play - etc, etc... I mean the ability to have moments like this in the game can be absolutely refreshing for the Lux player.

: Transitions :
http://imgur.com/Ycxao8D
Starting Skin "Light"
Fire + Nature = Magma
Fire + Air = Storm
Air + Water = Ice
Water + Nature =Mystic
Cross diagonally
Fire + Water = Dark
or
Nature + Air = Dark
[slayer-pantheon-rainbows]