Like Edmond said, the Regulator has built in over current protection, so if you try to draw too much current, (say the camera does need 2 amps to take pictures) it would shut itself down and you would possibly lose power to the camera.
Chances are, the 2 amp powersupply is sightly higher than what is needed, so you may be ok.
on the heat subject, any heat disappated by the V-reg is power lost from the batteries which means shorter battery life. If your flight time is very dependent on your battery life (you cant fly as long because your batteries run out, then you should look into a switching regulator