Well, first of the battle system we use here, goes to one ship vs another, one at a time, no matter the number of ships in a fleet (currently capped at five). So there are no multiple ship engagements where 2 ships fire at 1 at the same time.
We want to improve combat and perhaps the idea of all ships firing simultaneously in one combat is not a bad one. It is not even the first time it has been heard as we had such plans about 2 years ago (with fleet formation perhaps where we could also put ship size into the equation which is now only depicted in hitpoints).
This is probably a big discussion which however may need to take place before/alongside the
Ship specialization discussion, especially ship abilities. Feel free to open a topic in discussion/suggestion about it anytime. If not, I will be doing it as soon as we are done with Hideout. At any case, this is where we are focusing right after Hideout, as
proclaimed here so proper attention can be given now.
Back on your question, warfleet composition is a player's choice above all. It is closely connected to the player's style. Most fleet compositions fit a purpose and their owners are fully aware of that purpose and any limitations that come alongside. Maintaining a big fleet that can beat most other fleets can be very costly (and it can still lose). Most players like to put weak ships at the tail to reduce plunder bounty in case of loss. Or to cut on the probable level loss on sink chance.