There is no such thing as hidden E, just good and bad judgement of the enemy's E state
Although I'm from the camp where thinking dumping ammo is a shady way to get an advantage, I also believe the truly good duelers can figure out ways of overcoming these factors through ACM and judgment as you state here. I could dump ammo all day long but I still know you, Kappa, Bruv..... and gobs of other guys could whip me 9 out of 10 times purely because your ACM is more advanced than mine. This is the point I think Midway is missing. When it comes to the upper tier duelers, it's more about pilot skill than the airplane IMO.