I'm not so sure about the "turn the hips like "heck"" comment. A lot of the clips of good hitters I've seen show the hips turning about toward right field with not much pivot as the elbow drops into the slot and then fully opening in conjunction with the bat head coming around.
I think there are some kids out there popping their hips too hard and too soon.
This came to mind this morning as I was watching my son do dry swings in the mirror and his hips were fully open before his elbow even began to drop into the slot. Not surprisingly he's been hitting a lot of bouncing grounders to the left side lately and then hitting high flies when he tries to adjust. I attribute that to opening early and then rolling the hands a bit to get the bat around.
I had him try to hit ground balls during BP yesterday partially to show him that he was swinging up the back of the ball. Trying to hit grounders resulted in line drives.