The AI is Dumb. For starters.
Circle the sb with crusaders and illums and simply nail it. too much dps to be our regged and only a percentage of the fire hits the bases frontal arc. Keep the adjudicators to work down the missiles turrets. done deal.
Vasari Defense grids suffer from a sucky repair bay and Turrets with a special ability that, while being nasty against single targets like caps, is fckn useless when an enemy fleet comes knocking.
You might even have a weaker one since you need 10 tac points for phase stab. And a fully upgraded starbase.. well don't think about just how many ships the opposition can get for that cost.
Advent Defenses become supremely tough when they get shield mitigation due to synergys . The Damage bonus is quite nice too. An advent Base thrown into the mix can severely cripple any cruiser assault with mass disoerientation and, i nan considerably large area, nuke fleets for quite a lot of damage. And it will do it indefinetly. Throw in a squad of guardians and hosts and you can be assured some evil fighter treatment.
TEC Defense grids are very well rounded right from the get go:
The turrets can gain several Weapon upgrades which increase DPS and range and they get 2(!) extra "weapons". Missile swarm and meson bolt. Both increase the damage they can do. TEC Repair stations are the best there are in the game and the hangars have Flak build-in. Add a Tec base with Boons and the whole thing gets ridiculously tough.
Not to mention a real-life once in a lifetime "WIN!" button. Press it and the encounter is yours.
Fighting even a small TEC fleet made up of cruisers hoshikos and carriers alone, while they have such ga defense grid in their backs is suicidal at best.
By the time Vasari get Kosturas going, the other factions will have decent defenses in place. And superweapons on their own.
+ Any ships the vasari do have in such an attack behind the lines is missing at the frontlines where tec and advent fleets will wipe away the pitiful vasari defenses.