Not sure if you've already ruled out "Tomorrow's War," personally, I found the rules to be horribly inaccessible, but from what I do remember this sort of thing would be represented well.
Everything was based around the concept that rolling a 4+ = success, and what differentiated troops was the number and type of dice they were rolling. So, while a weaker, inexperienced, or poorly trained model might only roll one or two d6's, veterans could be throwing d12's.
So give your heroes some armor, training, and high-tech weaponry and keep the hordes of enemies relatively "green" and that may work.
A note: from memory, there are no point values, it's heavily scenario-driven. I think that actually lends itself well to a FPS-style game, but generating balanced forces may take some tinkering.