I loved, loved, loved the River of Light concept that was proposed for Animal Kingdom.
I to this day believe it is the best concept for a night time show at this park. The park is so low key, and is about letting it unwind slowly, and a slow moving, and slow building parade on the water would be perfect.
Anyways. That is a long killed concept, one that as far as I know is no where on the development calendar.
I will say that Avatar is probably the greatest hope for WDW right now.