I would like to point out that one of the commandos threw himself on top of a live grenade and survived completely unharmed, with just a minor dent to his chestplate. One thing you also have to consider is that blasters are plasma weapons, not laser weapons. Also another one of the commandos survived unharmed against a flamethrower completely engulfing his armor.
MC might be faster than the average human, but so is delta squad. The clones were genetically enhanced to be far more effective warriors than normal humans, and the commandos were enhanced even further. Not to mention, there's 4 of them, and only one MC.
And, i know its off-topic, but just for the record, MC would have no chance against 4 of the Null ARCs.
I never said blasters were lasers, but rather that their power output seems considerably lower than that of the Covenant weapons. Additionally, MJOLNIR armor can stand up to just as much damage, but likely has better shields.
And the commandos are certainly fast, but the Chief is decidedly super-human. I would pit him against many Jedi in terms of speed, and his armor provides considerable heft and strength augmentation for melee combat. I don't see the Deltas surviving a close encounter with Chief, especially not the ambush he's likely to pull using his motion sensor/radar.