Better to over-estimate the enemy and be proved wrong (as with the pi$$ poor Republican Guard) than to under-estimate them, and fall victim to complacency and under-preparation. Like in the Bay of Pigs, Vietnam, Somalia, the Lebanon, etc.
And if it's so easy, and if he and his henchmen can be so easily tracked how come Bin Laden's head isn't already on a spike, and how come we aren't already talking about it all in the past tense.
For what it's worth, these 12th Century tribesmen beat both Russian conscripts AND the Spesnatz and elite airborne troops, and it's all being fought on their territory. They seem no less dangerous than any of the other groups who've caused the US and Western military headaches and bloody noses in the past.
I hope and expect that the end result will be an inevitable US victory, but I'd be less sanguine that it will be entirely without pain and cost. I sincerely hope that I'm wrong and that it's a casualty-free walk-over.
I'm beginning to think that it needs to be decisive and quick on the ground, because public (and especially international) support seems to be waning.