This is going to negatively impact CM and Prae queues, no doubt - but probably not as badly as people are predicting. I can easily see 30 min plus queues, but I doubt we'll see them stretch to hours - at least, depending on what kind of incentives SE winds up offering. I can easily imagine folks willing to spend the extra time, due to the fact that these dungeons are faceroll easy, so it's a leisurely side activity they can do while watching Netflix, or even reading a book. Hey, if I'm gonna watch a movie, might as well rack up some Tomestones on the side?

Newbies will find the long queues discouraging, no doubt about that but it will only be for two dungeons that they're under no obligation to ever do again. They'll pull through.