Fighters: They are nice to bombard your enemies or attacking other fighters, but now when "all" can have them, they seem to lose a bit. What I mean is that they will not try and avoid enemies or their fire. In my last game I have 50 assault fighters, mainly built to attack enemy ships, they have one large missile with a 32 point warhead and 4 gauss cannons, these are small and low hit(17%).
I sent them to attack my opponents fighter, unfortunately they arrived after they launched at my main fleet, but now they are flying back to their carriers in a straight line and I am butchering them.
No finesse at all.
Of course they only had missiles, but something would be needed to give them a chance, more armour, own Gaus Cannons, a small CIWS to defend against fighters/missiles fighters, etc.
Fixes, if even possible: Some kind of dogfighting or jinxes were they try to evade fire. Big/slow heavy fighter-bombers are easier to hit and the other is true with small faster/nimbler fighters being harder to hit and kill.
If you played/read Star Fleet Battles, they have the rule that a dog fight makes it impossible to attack another target, some fighters have an advantage in a dog fight called "dog fighting" rating.