Martin, I would agree with you - sometimes an amateur does something better than a professional (after all, etymologically it means "someone who loves [to do something]"). In fact, one could argue that this is becoming more the case as the threshold for entry into an area of interest is lowered by a potentially increased availability of information, such as in citizen science. Regardless of whether one professes to make a trade one's job or merely one's occupation, though, it is necessary to hone skills and to refine judgment of quality.

So anyway, I agree that gradients and shadows are important to making a vector object seem physical (in this case, yes, those side windows could use it).
-Arlo James Barnes