Preds have advanced weaponary, MC is just a pussy cat compared to the predator, and the pred is a hunter, not a soldier, so he's more clued up on tactics and all that, and I'm positive that Predators would improve the technology in the future. With a quick stealth attack from behind the Cheif's neck is broken. Half a metric ton is unrealistic, and that armor does seem heavy, so it would slow Cheif down, even for a super human.