Certainly Giles bringing the Potentials to Buffy's home cut down on Dawn's alone time with big sis, but it just occurred to me that it could have been Giles himself, rather than all of those new girls, who broke up Dawn's training schedule. He could have seen or heard about the training and, in typical Giles fashion, as pseudo daddy, decided that Slaying was too dangerous for her, and talked Dawn into becoming, rather than a demon fighter (rogue or otherwise) a junior Watcher. Less danger, better working conditions, and a much greater chance of surviving long enough to see retirement. During his frequent trips to recover assorted Potentials, he could have assigned her teaching to Willow, with directions to teach her the fundamentals of magic, thus killing two birds with one stone, easing Willow back into magic, and keeping dawn pretty much out of harm's way. That would explain why, later in the year, she's reading spell books, in their native Turkish, no less, when she had been pretty much steered away from such things in the past.
There might have originally been a scene, or even a complete story line, showing something like that, but it had to be scrapped due to lack of tim.
