I didn"t know that dragon can spit fire with closed jaw
Is the fire physical (with methane bladders, etc) or magical? Even if it is physical (presumably it would have to be an extremely potent fuel source, if you never have to consume any raw materials), why would the jaw have to be open to use it? Classically dragons may 'breath' fire, but that is not necessarily the only way to go, especially in a world where humans can cast fire spells (or is fire coming out of a wizard's hand unrealistic, as well?).
Form your own opinion. The people enjoying the game have better things to do than come here and post. Complaining, however, is a different story.