Strangely, River Journey it reminds me of Pirates.
Not the Pirates we know today, but the original Pirates of the Caribbean. It's not supposed to have a story, nor is story important. It's just a chance for you to see the nature of the planet in one of it's better forms (as I have doubts on the Nighttime aspects of the land itself), in a calming environment.
If I were to go in, I'd do the attraction at night. Just so it's much more of a seamless experience overall. While I would do the River Passage in the night; I'd most likely do the Banshee during the day, depending on how it is handled.
But I am more excited about Banshee, in the technological aspects of it.