I don't necessarily disagree, but you already DO get more perks at least.. 
True.  I think that is fair and well.  However, when King Pick is using his Tempest in hopes of earning a high rank he should receive less credit score wise than of someone were to do they same thing in a P40E.  If ENY was factored into score/ranking, there would be an entirely different set of people in the top 20.  Those fellas that are experts in the P38's, non-K4 109's, P47's, etc, would rule the show for the first few months.   
off topic: I think it is funny to hear people cry when they earn a single perk point for shooting down an Me262 in their P51D, La7, Spit16, Tempest, etc.