Industrial capability: The Empire was capable of building the Death Star in about a year and consisted of at least a million inhabited worlds. Add in the other major Star Wars civilizations such as the Galactic Republic, and you have a very large and powerful industrial base. The Star Forge would amp this up.
Numbers: This is sketchy. The Empire had about 25,000 star destroyers, but had the capability to produce many more and also had many smaller ship types. Then there are other Star Wars civilizations before and after the Empire that had their share of star destroyers as well. Combined with the Star Forge, the totality of star destroyers of a united Star Wars Galaxy could number in the millions, and there are also other ship types. As for ground troops, the Galactic Alliance had about 100 quadrillion citizens, so there would have to be enough military and police forces to police that many people. The CIS had about a quintillion battle droids, which is a HUGE number.
FTL travel: Hyperdrive has shown to be able to travel accross the galaxy in a matter of hours. Warp drive can often take decades to do such a thing. Transwarp cannot be maintained for long periods of time, often requires external attatchments and is not known by all major ST civilizations.
Space weapons: Turbolasers often generate hundreds of millions of gigawatts of energy. The Enterprise in comparison had main phasers of about 3.6 gigawatts.
Shields: Star Wars shields have heat dissipation in the tens of trillions. The Enterprise in comparison has one in the thousands. Also, Star Wars has planetary shields capable of resisting prolonged orbital bombardment.
Ship speed: although star destroyers do not appear to have a very high non hyperspace movement speed, starfighters have a speed often exceeding 10,000 km/hr.
Support ships: Star Wars has starfighters of which Star Trek ships would have little defense against. Even starfighters would have enough firepower to penetrate most Star Trek shields and are faster than what Star Trek ships are used to.
Superweapons: The sun crusher can generate supernovas in stars and is virtually immune to all known forms of conventional weapons. The galaxy gun can destroy a planet from light years away. Centerpoint station can destroy or even move even a star from light years away. The Death Star can destroy a planet and has a huge number of powerful turbolasers and other defenses. Using the Star Forge, these could be mass produced.