First off, I would like to say I love Sins and play Vasari almost exclusively. But there are some things about them that I think need improvement.
Reintegration: 18 hull/s? 18?!? Thats pathetic. 18 hull/s wont even cancel out an Illuminator. Buff it to 20 or 25
Repair Bays: 15 hull/s? A SINGLE Javelis could convievably kill something being healed by a Vas repair platform if given enough time. Bring it to 20-25.
Colonize: The Egg's Colonize ability is uselss. Advent get a humgo resource decrease. TEC's is weak too, but at least they get to save some money. I would think that Vasari would be the ones to get a break on the cost of upgrades with all their fancy nano-tech and advanced construction techniques (*COUGH* Enslaved Labor, Optomized Construction *COUGH*) but for some reason they get a 20% structure build time. Thats not good for ANYTHING. Decreased cost for structures prehaps?
Deliverance Engine: I know its not Vas, why do Advent get instant friendly culture AND +15% damage? They already get +6 mitigation in friendly culture, now they get more damage? They already do the most damage out of the three races. I would think that they get an extra mitigation increase with the Deliverance Engine, while Vasari get the damage increase with the Kostura.
Synergy: There really isnt any. Its not like TEC where you get useless Synergy (The Akkan's incresed accuracy ability, even though accuracy is perfect by default), or OK synergy (Dunov + Kol = Invincible Kol, but its till a Kol so it doesnt do a whole lot), Vasari get Microphasing Aura and Repair Cloud. Volatile Nanites + Phase Missile Swarm either requires you to wait until the enemy is almost dead anyways or have 4 Desolators. Given that Vasari ships should be tough to kill, I would like to see repair cloud last longer, and some abilities changed to benefit the fleet's longevity.
Just some ideas