The whole imbalance comes down to one simple fact:
(Most) Fighter pilots cannot kill bombers before those bombers kill a battleship, or even a cruiser.
The capship is not designed to dodge and evade, it's only defense is absorbing damage until those escorts kill the attackers. If the escorts are incapable of finishing that task quickly enough, the cap is going to die, there's no way around it.
Now, as has been said, the 'heavy bombers' like the fafnir and barghest can be killed quickly enough by fighters, because they are not as capable of dodging fire from fighter-type craft, and due to slower sped and larger size they are more vulnerable to cap fire as well.
The other bombers though... they have too much agility, too much survivability, and too much firepower.
There's really two things we can do, at least in my mind, to resolve this situation:
1. Nerf Bombers. Everyone hates this idea, because... well, everyone flies one. At least, it seems like for as long as I can remember bombers have been the dominant shipclass on this server, and are as all-around effective as you can get.
The idea would be to take every 'light' bomber (basically, all 'normal' bombers right now) and reduce their armor to fighter-like levels, reduce their power generator to be barely capable of firing a single supernova or nova at a time, and nerf them down to a single torpedo slot instead of two. Basically, turn them into heavy fighters that can tote some anti-cap weaponry.
Over time, the plan would be to convert or replace these with heavy bombers like the fafnir or barghest.
2. Buff Fighters. The bomber pilots still seem to hate this idea, but tough luck, something needs to change.
My plan would be to restrict fighters to class 9 guns only, but make bombers ONLY able to use class 10 guns. That way we can keep class 10 gun balance like it is now (600-700 M/S projectile speed, high damage, low refire), and rebalance fighter-specific guns (class 9's, primarily) to have much higher projectile speed and refire rate.
If we gave fighters the ability to use 1000m/s or so projectile speed guns, they would have a much easier time killing bombers in an acceptable amount of time. The other side effect this has is making fighter vs fighter battles shorter, so we dont end up with hour-long furballs every time an event is planned.