I'm jumping in here late, but trust me, dude, you just need a new gym. This coach sounds like she was probably a typical cheer diva in her day. She was most likely a "point flyer" and thought the world revolved around her. She has not learned the finer art of building a group of individuals into a cohesive unit. She expects kids, and that is what they are, to learn and retain changes to a cheer routine in one practice. She singles out kids who do not adhere to her expectations. She is not a coach, she is a dictator.
Coaches, in all sports, have to have two things leadership skills and a deep understanding of the sport. They believe in things like reciprocal loyalty. My athletes are loyal to me, because they know that I will walk through the fires of hell for them. Even when they are in the wrong, they know that I will remove them from the situation, and then correct them privately. Coaches have the heart of a teacher. These changes in the routine should have been planned out far in advance, with the goal being to steadily increase the level of difficulty throughout the year. A well-choreographed routine will score similarly under any scoring system with only minor adjustments.
Here is my advice:
1) If there are other gyms in your area, start calling them. Explain that you are unhappy with your current situation (no reason to play the blame game, or go into details. You're an unhappy customer, and that is all that should matter to them). Ask if you can come in and watch a practice or two.
2) Find one you like
3) Finish the season where you are, for no other reason, than because it's the right thing to do
4) Based on what you've said already about this joke of a gym where you are currently, don't be surprised if they get wind that you are looking and relieve you of your obligation for the rest of the season. Tell them to go do something anatomically impossible.
5) Gather all the information you need to make an informed decision about which gym will become Gym B.
6) If you have problems at Gym B, consider a long self-examination process and make certain that you are not just expecting too much out of people. All Star cheerleading is very expensive, and the price tag and lead some people to have expectations that are too hi