I was thinking about the problem of the battleships and then I remembered the old days when I flown the barracuda and the anubis, and then I noted nobody is flying those ships.
Due to the level 30 limit, no battleship can attack a fighter bellow level 30. So, thats the idea that I propose for factions so that they can have battles between fighters only and nobody be able to switch to capships: start to use the old ships.
My idea was to divide the ensign rank into five:
Ensign 1 star: uses a light fighter, like the dagger.
Ensign 2 stars: uses a heavy fighter, like the stiletto.
Ensign 3 stars: uses a light fighter mk II, like the scimitar.
Ensign 4 stars: uses a heavy fighter mk II, like the sabre.
Ensign 5 stars: uses a super heavy fighter or a bomber.
The same can be done with lieutenants and wing commanders. The two first ranks will be under level 30 I think, thus evading the use of capships. There will be no need to spend too much money with new recruits. And when the new recruit get two stars, he can maintain the old ship, thus having two fighters.