What im thinking is;
If i make the voltage divider equivalent resistance large enough, then current will be directed into the base of the BJT. When drawing the small signal model, the drop across the internal resistance (what we call r_pi) is what sets the gain so by decreasing the voltage divider equivalent resistance the base current is decreases. By decreasing the base current the voltage across the small signal r_pi is less. The drop across r_pi is one parameter that controls gain and the less the drop across r_pi is, the greater the gain...
is this clear? does this make sense?