The whole box by which the pvp is involved is too small to begin with, therefore the place where combat can take place cannot be balanced. Let me explain.
As realistic as I want to make this, a Capital ship should have weapons that attack at huge ranges. 5k is nothing, how about 100k range? Most cap battles are fought in a 3k cube
Fighters have a combat effective max range from 1 k though there are those that can attack at greater ranges but we stick to a 600m combat box. As two light fighter players once said, 'we'd have to play for 48 hours until one of us actually died.'
No one here would honestly want a balanced game because some fighters, ships, equipment would never ever be used because a ship of the same class has one or two advantages you don't and typically wins. Yet if Im more experienced then you, I can use my ship to its maximum potential while you don't even know how to strafe. My point is, game play here is like sticking marbles in a 1 foot cube and shaking it around. The effectiveness of a bomber vs a fighter in tight quarters is cut when you only function in a small box. You're essentially trying to guard a brick from being hit in a box that barely can hold it in the first place.
So far, pvp here comes down to two things
How well do you understand the in game physics.
How well can you use your ship in those physics.
I keep hearing a story about a light fighter forcing a cruiser to land because the fighter used its game physics to its maximum potential while the cruiser player was most likely looking for a quick kill. So to hear a pair of fighters cant ward off a pair of bombers is nothing surprising to me. In real war conflicts, escorting transports and cargo ship were always the hardest missions to undertake, accounting for more ship loses than actual war ships. Some say a Battleship Solaris boat doesn't work. It works perfectly for me because the bombers function in the box they always seem to operate in which is just too close. Bombers shouldn't win against as much as they do in disco fighter but they do. One hit wonders and game lag.
Yes, things have balancing issues, but you're asking to balance a war ship and a fighter in a rubix cube playing area.
Come back when you've figured all that out and go from there. There are compromises that can be made to make this work more, but many want a ship that can do it all, and that is not balanced or realistic. Welcome to the gaming world. There is a drive to work in groups as it should but again, the area to work in is limited to say the least.
Sometimes, when all you want is to gain your freedom, you must be willing to risk it all.