WHAT was that Colonel thinking?
While "Massed" units are indeed the best for combat, that does NOT mean shoulder to shoulder! Optimal spacing for massed armor is 50-100 Meters, hull down whenever possible. That is as close together as you EVER want your tanks to get. Additionally, WHERE was the overhead? Recon? Armored units always move with recon Humvees scouting ahead, and support units bringing up the rear.
I didn't see a single actual hit by a defending weapon on one of the mechs...
The way it SHOULD have gone, would be for the enemy armored force to be detected at about 50km (or more) by overhead imagery, either Satellite, recon plane, or UAV. UAVs (if available) should retain contact with the enemy throughout the approach, with further intel reported by the DOZENS of recon units (for an armor force of that size). Since the M2 Abrams is more than capable of getting tank kills with its primary weapon at 2500 meters, combat should have begun (and ended) with a single shell striking each mech, going through-and-through, and leaving them burning on the ground. Sandstorms have no effect either on microwave radar rangefinders (they would stop the laser ones though: good thing there are backups) and the thermal sights on the tanks would have shown the enemy clear as day. All this is assuming that brash young officers in the scout platoons don't light up the enemy with Javelin missiles first, (which would be less effective as they try for a top attack by default) but still should be more than lethal enough to take out the targets.
For mechs to be in any way realistic, they must have not only better energy systems than the tanks, but better (and lighter at the same time) armor, superior weapons, equivalent ammunition, superior stealth systems covering both radar, visual, and infrared, and some way to ignore the laws of physics to permit them to turn on a dime, and ignore the coefficient of friction between their feet and the ground.
And at that point, just build a spaceship and shoot them with an orbital laser because you are spending that much money anyway.
