EM in SFC3 is Erratic Maneouvres, NOT evasive Maneouvres - they are two separate things. Evasive Maneouvres is a combination of Erratic Maneouvres and changing the Speed & Direction of your ship.
With Primary Weapons, Phasers & Disruptors, AV has little effect, in fact I believe Primaries have a 90% chance of hitting, regardless of AV. All bar 1 Heavy Beam Weapon also has the same properties as Properties as Primaries (the Klingon Ion Cannon is that weapon). I don't have the source code, so I can't prove this. But after 18 months of testing, I've yet to see AV truly affect Primary Weapons.
AV only really affects Heavy Weapons, specifically Torpedoes, and for those weapons, it DOES make sense. We are told in Trek Canon that a Photon Torpedo has only limited fuel for adjusting it's course. If a two ships are travelling straight towards each other at 1/4 impulse, one fires a Torpedo and the other executes a 90 degree turn and accelerates to full impulse at the same time - then that Torpedo now has to track the ship itself, as the change in Speed & Direction happened AFTER the firing of the weapon(the computer will have fired it along the the best possible course it can calculate). It doesn't mean the Torpedo is going to miss, but the actions of the ships pilot in engaging that evasive maneouvre increased the chances of the weapon missing it's target.
If you change the situation, two ships are flying parallel, but in opposite directions. The same Torpedo is fired, but the defending ship has to make far less effort to avoid the torpedo, because even a small change in direction makes it difficult for the Torpedo to adjust it's course and hit it's target.
In SFC3 - Angular Velocity is not the primary determining factor in weapon accuracy, two factors are, Range - and the difference in Size between the two ships. If a Fighter is flying against a Battleship - the Fighter is unlikely to miss, as he has such a huge target to hit, but the Battleship can miss the Fighter, because the Fighter has vastly superior speed & maneouvrability, it can evade fire quite easily.
In truth, the biggest issue with Weapons is in both SFC3 & SFC2 - and that is Accuracy at Range. Why does a Torpedo miss a stationary target because the weapon is being fired at Range 30? The computer is advanced enough to calculate the correction direction to fire the weapon, so why does it still have a chance of missing?
If you want to play a game that actually gets Starship on Starship physics right, then play Bridge Commander. Phasers & other Beam Weapons never miss in Bridge Commander, but with Torpedoes & Pulse Weapons, you have to make sure you fire them in the right direction, Torpedoes have a limited tracking facility, which can compensate somewhat for evasive maneouvres & a bad angle of fire - but if your torpedo tube is perpendicular to your opponent, that torpedo is going nowhere near your target.
With Mods, you can create anything, a weapon that can loop around and home in on it's target every time is quite doable.