I hope you're right and I'm wrong, but I don't see it. I think for a significant line drop to occur within a park, something "new and wonderful" will have to be in that park. For example, I don't see SW having much effect on Na'vi, but would have an effect on other HS lines, including Slinky Dog. Not so much with the standby line, as more people will be in HS, but with the fastpass availability, since many will want to use that tiered slot for one of the SW attractions, not Slinky. Similarly, MK is such a popular park that I think 7D lines/fastpasses won't change much, but when Tron opens up, they might.