If anyone isn't aware, the starting fleets are defined in XML and are quite easy to modify, they're at AI War 2\GameData\Configuration\FleetDesignTemplate\CMP_StartingFleetDesigns.xml
I started up a game on Diff 7 with the starting fleet modded to be V-wings, Pikes, Concussion Corvettes, and Assault Frigates. Very first planet had a Sabot Guard Post surrounded by Acid Turrets and covered by a force field. Even with all my ships at Mark I, I was able to kill the Sabot guard post before I lost any of my Assault Frigates (though I did soften it up slightly with some Mark II Concussion Turrets and a Mark II battlestation). Quite happy with that as a starting fleet! Most of your offensive tech upgrades also upgrade some form of your defenses: concussion corvettes go with the gravitic battlestation's concussion turrets, pike corvettes go with the pike turrets that all command stations get, and assault frigates go with the stationkeeping assault frigates.