I think it's an interesting dilemma, for sure. I'm rooting for all this to succeed, but I think there's one major flaw, and that's there's still not nearly enough to do at the park. Even with the addition of two Avatar rides, I'm not sure it makes a difference when it comes to people staying at night, especially when those two rides will probably be the things everyone hits at rope drop.
Yes, Avatar will look awesome at night, but outside of people taking a walk through it when it's dark, is it going to keep them there longer than an extra 10 minutes in the evening? I'm not sure. And if RoL is as much of a mess as it sounds, I don't think that'll do the trick either.
Again, I'm rooting for nighttime DAK to succeed, but I just don't think the park has enough nighttime offerings that anyone really wants to wait around to see.