I have found the cure to impossible-to-fly quadcopters!

Throttle curves! I have no idea why I didn't think of this before. The most difficult thing about flying a quadcopter is controlling the throttle; it is always either too high or too low. I love programming exponential control for my roll, pitch, and yaw, but I forgot that throttle curves would allow me to do the same for my throttle control. Now the middle 50% of my throttle stick only maps to a 15% change in throttle. The difference is astounding. 

Now that I have telemetry working with the Arducopter, I think I will be able to make useful progress on that project. I will make a video soon.