i don't think it is exaggerated. I think if you'd just started to fall, like off a cliff say. an expression like this would be exactly what you needed. would you seriously have a stoic face if you were falling to your death?
I probably would not have a stoic expression either if I fell off a cliff or such. Well the expression may be stoic if they made their piece and just are excepting that circumstances beyond their control have caused them to fall off this cliff and there is no way they can stop it in time.
I saw some other other ones in this series and some were definitely more exaggerated though only a cartoon character could of got a more exaggerated look then your most exaggerated expression.
No that is fine the stocks of yours I have seen so far seem rather useful. Also the part about the cartoon character being the only thing that could get more expressive was a compliment to how expressive the person in some of the images