Floaded, I really feel ya, man. I have similar issues with not receiving material in enough time for everyone to learn. There are several musicians with varying skill levels and out of 12, about 3 or 4 of us can pick up the material fairly quickly. The rest aren't used to playing by ear and need time. It really bothers me when they throw stuff on us last minute and only about 4 of us are following, and even then we're faking it.
I also feel you when you talk about seeing an opportunity for improvement, and when you make it known, no one else wants to do anything about it. Most people are more comfortable maintaining the status quo. It's FRUSTRATING to the point that it bothers me when I'm not even at church.
With your issues, man, whatever you decide to do, just remember to keep your head up. Don't EVER give up no matter how frustrating it may be. Do some personal meditation and praying to help you decide what to do. You may find you need a change of church, which is okay. Or, you may find that staying where you are is the best decision.
One thing that may help put things into focus is understanding how much time and energy it would take to persist in really making a change that is needed. Then, think about what you would have to sacrifice to do that and if it would be worth it. In my case, the sacrifice would be my academics. I'm in Tallahassee now to get a degree, not to play. That's just a blessing that came along with it.
Stick with your focus and let everything else go. You can only fight so many battles at one time.