I've come up with a few ideas for a sins expansion. It could be called Sins of a Solar Empire: Punishment. I've come up with a new race who are the ones whom the vasari created (as said on the back of the box) and who they are running from. You are most likely not going to read all this though. The parts in bold are the best bits so u don't need to look at all of it.

Praxid Union
Prefers ice planets. Focus on bounty collecting. Units have a spiky green and crystalline appearance. Praxid units have a moderate cost but are much more flexible and versatile then their counterparts. Their signature weapons are electron emitter cannons which shoot lightning bolts and suicide weapons. frigates and strike-craft can be upgraded to suicidally destroy enemy units and structures. Planet bombing weapons used are proton bombs. It is unknown as to the true name of praxid units as they are referred to as popular TEC military nicknames. In fact, it is unknown what this robotic race refers to it self as the name Praxid Union come from the name of the first TEC planet that was attacked. During this initial assault, nobody escaped.

Upgrade Trees
Expansion tree (civic)
Scorched Earth-colonization upgrades and planetary bombardment upgrades.
Power-mining and trade upgrades and structure upgrades
Advancement-transmission tower(broadcast centre) upgrades, unit detection, long range phase jump upgrades etc.

Conquest Tree (military)
Concepts-unlocks advanced military units and tactical structures.
Pursuit-unlocks weapon upgrades
Protection-unlocks armor, hull strength and sheild upgrades

Experimental tactical structure(super weapon)-Avenging Harvester. This structure sucks huge amounts of resources off an enemy planet.

Electron Emitter Platform-defensive turret with 4 electron emitter guns.

Countermeasures Platform-defensive structure that passively reduces the accuracy of enemy weapons greatly.

Capital Ships
I have not explained the function of cap ship abilities as this post would get too long.
Angry Carver-(battleship)
armament:2x heavy electron emitters, 2x pulse laser batteries, 2x electron emitters, ship-to-planet proton bombs (fore)
3x heavy pulse lasers (port/starboard)
special abilities: storm barrage, overcharge, final act, terrifying presence

Vicious Swarmer (carrier)
armament:4x electron emitters, ship-to-planet proton bombs (fore)
2x pulse lasers (starboard),3x pulse laser batteries(port)
special abilities:Advanced targeting network, deploy flak platform, plague, blackout

Fierce Slasher (support, planetary bombardment)
armament:2x heavy electron emitters, 2x heavy pulse laser batteries, ship-to-planet proton bombs (fore)
2x pulse lasers(port/starboard)
special abilities: Sun flash, neutron munitions, reputation, hailstorm

Raging Ripper (support/combat)
armament: 1x heavy electron emitter, 3x pulse laser batteries, ship-to-planet proton bombs (fore)
2x electron emitters (port/starboard)
special abilities: traction beam, point defense, induce madness, remorselessness

Furious Reaper (support/colonization)
armament: 2x electron emitters, 2x pulse lasers, ship-to-planet proton bombs (fore)
2x electron emitters (port/starboard)
special abilities: colonization, juggernaut, inspiration, beacon

Frigates

Smoke Slicer (colony frigate)
Night Ravager(light combat Frigate)
Dusk Devourer(siege frigate)
Gloom Hacker (flak frigate)
Deep Piercer (long range assault frigate)
Grey Ghost (scout frigate)

Cruisers
Shadow Stinger (support cruiser)
Black Stunner (support cruiser)
Dark Thrasher (carrier cruiser)
Twilight Stabber (heavy cruiser)

Please let me know what u think!