Deciding which is the most important admittedly does add a subjective component into the process of ENY evaluation. Still, that's no reason to give up, because we can at least come to some agreement as to how to begin. I think we all agree that speed, firepower and turn deserve first rank. Second rank might be climbrate, low/high speed handling and durability; cockpit visibility third. This is just an example of how we could begin to weight the different abilities of fighter aircraft. I'm not sure how much weight I would place on ordinance. What do you think? HTC sometimes places a lot of weight on ordinance, e.g. P47N, and sometimes an aircraft that carries little or no ordinance can also have an ENY of 5.
Regardless, implementing an imperfect system for giving objective ENY values to aircraft is better than mere guessing and arbitrary decision, which is what we seem to have now.
The hard part is actually creating a formula and a system for assigning numerical values to different things like speed, firepower, ordinance capacity, etc. One thing I can think of would be to simply assign different classes of rank for different maximum speeds. Anything over 400mph on the deck is 1; between 375 and 400mph is 2; between 350 and 375 is 3, etc. These ranks can take the place of variables in a formula.