I have experimented some with this and would like to have a discussion about balancing this better...
Now I do wonder why there is such a hard focus on attacking enemy Escort ship that usually have a low threat value, it makes very little sense. It also get worse when you figure in how this can be abused by an observant player.
In essence you can do an all fleet with only Escort and Guardian ships... due to how the priorities are constructed such a fleet will be completely OP in regard to a more balanced fleet against the AI. In this fleet Escorts have 90% defenses and 10% weapons while the Guardians the reverse. The fleet would then have about 1/4 escorts and 3/4 Guardians, or perhaps even less Escorts.
There is such a high focus on targeting Escort ships that by the time any ship want to target any of your Guardians the battle is practically over. The only ships that will go after your Guardians are Interceptors, but Interceptors start so well forward they they die first anyway and your Guardians are going to prioritize them first anyway.
There should not be such a high focus on targeting Escort ships.
Capitals should go directly against other Capital/Escort/Support/Assault and defend Capital
Assault ships should target Capitals/Support/Escort/Assault.
Interceptors should go for Support/Assault/Guardians/Escort.
Escorts should go for Assault/Interceptors/Escort/Guardians and defend Capital/Support.
Guardians should go for Interceptors/Assault/Guardians/Escort and defend Support/Capital/Escort.
This would make the battles less easy to optimize and Support ships would need to keep some defenses if they want to survive. It would also give some incentive to actually put weapons on Escorts and other defensive ship types while you will need defenses on your Capital and Support ships.
In the battle viewer I want to see a wave of Assault and Interceptor coming in and my Capital ships will direct their attention on enemy capital ships once they get in range not the enemies Escort ships. My Escort will most likely keep focusing their fire on enemy Assault ships who attack my Capital ships and my Guardians will attack any Interceptors that races for my Support ships.
The Battles would probably be more dynamic and chaotic and there would be much less focus fire on one class of ships throughout a whole battle. Since I figure that a ship will mostly target ships with a higher threat value if there are several ships to choose from these priorities will provide some more interesting results in my opinion.