I was rereading first strike and I just reread the Reach section. It seems like all the spartans were at a huge disadvantage, not the outnumberment, but the thermal volocity drop had injured many of them and took out a couple of their shields and other significant systems. Here is a quote:
Fred initiated a diagnostic on his armor. The hydrostatic sub-system had blown a seal, and pressure was at minimal functional levels. He could move, but he would have to to replace that seal before he would be able to sprint or dodge plasma fire. Page 15
Meaning that most of the spartans had either no shields, or systems that let them move as fast as they should be able to. Others had injuries that hassled them greatly six could not move from a fixed position, everyone else had minor things, and four KIA all from the drop. Now I know if all had minor damages and no blown shield generaters or other broken systems they would have held off the covenant even longer. The most craziest part was the spartans from the last transmission in the book said they were being overrun but not dead yet. Meaning they were still holding off thousands of covenant infantry. All of this is on pages 31-32. Now here is the crazy part most probably did not get overwealmed because at the end three covenant cruisors broke through the atmosphere and glassed the area near the spartan. So in the end I learned the spartans could of actualy done way better if they did not get glassed and more would have been alive. This is a theory but I do have canon evidence to back it up greatly.
You can't play halo wars until you see this video
http://www.escapistmagazine.com/videos/view/zero-punctuation/645-Halo-Wars
I've been perma-banned at bungie.net :(