I build about 100 explorers with long range scanners and park them one per sector or so. That covers all of a 10x10 galaxy. No point to putting the LR on warships, it eats fuel during battle like crazy.
Lonnie Courtney Clay
You like to powergame, I don't. The explorers are also exploity, because they can park where the AI won't appreciate/allow a monitoring base.
If you powergame a bit less, you may consider that a ship class may not be much of a fighter. I feel I basically need 3 kinds of fighting ships. The main fleet ones, the carriers, and the raiding ones.
Cruiser for main battle fleet "fighters".
Destroyers for more roaming. Frigates if you prefer that tag.
A 2 cruisers + carrier fleet works a charm for mopping up small stuff as well.
The Capital can be the fleet control ship. Scanner, fleet modules, high defense. Not so much weapons, maybe some long range ones, or a death ray.