In my eyes, Blake made up the right-pec drill to completely isolate out all the parts that screw people up from even finding the "hit" and was trying to get to the meat and potatos of the throw. So, with that in mind, you shouldn't be worrying about your hips, reachback, spinning, kicking, turning, weightshift, etc... Because those are all the things that people screw up which makes an actual "hit" impossible to achieve. You're supposed to add all that stuff back in (one at a time) after you've got the meat and potato's figured out.
I don't think it's really written anywhere, and that's what messes a lot of people up with it -- including myself. Since there's no official "rules" of the right-pec drill, people just feel like they're handicapped, and try to get power from all the other sources (weight shift, hips, reachback, etc...) which defeats the entire purpose of the drill.
I personally like brad walker's closed shoulder drill because, while it's very similar to the right pec drill, it's very clear on how isolated you're trying to make things, giving you a better chance at success!