Yeah except hyperspace travel isn't as accurate as Forerunner slipspace travel hell even the covies can drop an armada of ships out of slipspace with 0 collisions. It's quoted that the covies can bring ships to bear out of slipspace with an accuracy around 1 Atoms size from where they intended to drop. Also Halo's production rate is much higher then Star Wars they can tear an earth sized planet down in 9 days and use those materials to create a Halo in the same amount of time. Ship wise dreadnoughts coming in at beastly sizes one of the smallest (the Didacts own ship) comes in at larger then the Death Star. Also fire power wise it takes a handful of star destroyers to level a city. While in Halo a war sphinx which comes in at 12 meters in height and about 20 in length can vaporise cites and upturn continents almost on there own. And that's just their single attack crafts similar to an X-wing or Tie fighter. They also have sentinels capable of grouping up and joining their firepower/shields the fire power of around 50 of these things is enough to hit a covenant flagship from stem to stern with full shields in just one shot.(onyx innards was entirely comprised of trillions of these sentinels) Production wise they can create a dreadnought vessel in just a couple of days,war sphinxes in minutes and the sentinels mentioned above takes a mere 6 seconds per unite to construct and be battle ready. Now add ancient humanity and san'shyum to this who where on the same technology level as the forerunners though slightly behind in slipspace engineering and you have 3 races who can send out trillions of remotely piloted ships without losing a single troop and can be continually mass produced at such a scale as to take over a Galaxy within a few weeks.