For single or multiplayer?

In general though, despite some complaining on the forums, carrier spamfests don't work all that well on experienced players due to the game having some very good mechanisms that scale up with the number of strikecraft (like the Kol's Flak Burst that just hits everything in its rather large radius, the more strikecraft the more it hits, or the Advent's Halycon that pushes all strikecraft away and also damages them). These make it pretty easy to knock out masses of fighters/bombers and leave the spammer a sitting duck with the hostile construction penalty.

And there really aren't useless ships. They all have a purpose, though some are more specialized than others and may not always see as much action

Heretic. I love playing FFA games. To each their own.

There is no right or wrong way to play Sins.  This is one of those great titles that gives you all the tools you need to create your own epic story of interstellar conflict.  As such, I recommend just trying all sorts of different set-ups.  I've been fooling around with different combos since I got the game and even the ones that didn't work out all that well still proved to be great fun.  Just consider every game as a seperate chapter of victory or defeat in the larger Sins universe!