Night elves see a bonus to Quickness that adds a 2% passive buff to movement speed and a completely new racial, Touch of Elune, which adds 1% haste at night and 1% crit during the day. Shadowmeld is unchanged.
I was trying to come up with something pithy about a buff that changes based on time of day and how that would be a pain to try to get haste breakpoints correct, but the first comment I read said it so very concisely:
I think raid leaders should be able to make whoever came up with Touch of Elune take a drink whenever someone asks them if they can move the raid forward or backward an hour to get the better buff. Let the true min/maxing begin!
Let me just take a moment and be thankful that I am part of the Horde, and all raids I lead are Horde raids.