Ugh. Game just ended about an hour ago, so I am just giving my first reactions, without having reviewed the game carefully.
Obviously, the defense was completely overmatched. It's not just that the Saints put up a lot of offense, it's that the Giants seemed completely unable to keep up with them at all. Saints had much more team speed than the Giants defense and that's on the players being not athletic enough. But there were way too many mental mistakes, inability to line up properly and getting fooled on every Saints wrinkle. There were way too many long plays (20 yds +) and the Saints moved down the field and scored way too easily. It didn't help that the Giants offense didn't get into the end zone in the first half, but that's no excuse for the defense. The speed thing and getting beat athletically is the players shortcoming. But not getting the plays in on time, being entirely predictable on defense, not disguising anything so the offense knew exactly what they were going against, being disorganized, not lining up properly, not protecting the middle of the field - that's entirely on the coaches.
The 3-safety look is supposed to be a change of pace, a switch to confuse the offense occasionally. but when you give the wired helmet to Deon Grant and he's responsible for calling the plays and lining everyone up, it is advertising and declaring that you will run the 3-S look virtually the entire game. So not only did the pass rush not get there and make Brees uncomfortable, there was not disguise or surprise in the defense; Brees knew exactly what to expect. Maybe the players aren't god enough, but they are being exposed and compromised by the coaches not putting them in the best position to be productive.
Deon Grant has lost it. If you put the ball in his hands like Brady did a few weeks ago, he may catch it. But he can't play pass coverage, and he can't tackle. This is the second time he was 1-on-1 in the open field with a ball carrier and he completely whiffed on the tackle resulting in a TD. The first time was Fred Jackson on the Bills, but at least he is a RB. Last night, Brees beat him right up the middle.
On offense - the first time the Giants moved down the field, Eli threw the INT in the end zone, (which Ballard should have made a play on and caught or at least prevented the INT) and that was the only time they got close in the first half.
Way too many sloppy/mental mistakes on offense - too many dropped passes, two fumbles, and Nicks stepping out of bounds twice when he had lots of green in front of him.
I don't know what was up with that faked punt. Not a great try.