If the button was close to the firing controls then it would be usable with the "toggle" control type. I'm still really enjoying the game, and the progression overall is much more solid in this sequel so I'm trying to compromise with the missile controls. The movement off control might the one I can use best if I get used to always moving while shooting. Another way to activate missile mode could be to double tap, or even triple tap the control pad or firing controls. Of course, this would only work as a toggle but I think it's worth a try in beta. My major concern with the current options is that I have to do something different with my left thumb for the duration the missile mode is activated. It's either hunting for a button or keeping my thumb off the controls. In the double/triple tap scenario I could just quickly switch back and forth between modes without feeling odd. But that's just my personal experience with virtual controls on iPad.