When you miss the joystick, it should go to the position of where you clicked near it, similar to the dynamic thumbstick.
In any hard obby game, I tend to be very concentrated that i forget where the jump button is. When i try to jump when it is time, I tend to miss it alot, and fail. I think that this will be great for mobile devices, Especially for big screen mobile devices.
Make it an option in the settings bar, By Default it should be turned off. It will be useful for hard obby games, like Tower Of Hell, etc. It will help big mobile screen users to not miss the jump button.