Do you mean Human vs Human, or the Human-Covenant war? In human to human, I would have to say it would be the same as if everyone wasn't augmented. Think of it this way, if all humans were just their normal selves, there would always be people stronger or weaker and with better training and tactics. Same goes for augmentations. If the entire human military was augmented, there would still be stronger or weaker individuals with better training and tactics. Now, for the Human-Covenant war, I'd say the Humans would have easier times in ground engagements (even though they were fairly good on the ground).