The thing with a movie opening like TFA is it resets the bar, and it's hard to compare it to anything else.
I don't see any of the Hobbit films drop offs effecting this movie, because there was a lot of mixed reaction to those films. They certainly weren't as popular as the LOTR films. We're on totally new ground here, having a film like this perform this way in December is unheard of.
The big thing to consider is how Friday will effect the weekend numbers. I would say you're going to have a larger drop on Friday than normal, but a bigger recovery on Saturday as it's the 2nd biggest shopping day of the year and people will be out and about.
However let's be honest here guys, this film can have a pretty big 2nd week drop and it's still easily getting the 2nd weekend record, but Christmas day is going to effect things.