There are some indications that the Giants are getting out-coached by their opponents. As much as the last two games may have exposed some weaknesses in the personnel, I think the coaches are at least partly to blame for not putting the players in the best position to succeed.
Cardinals came in with a novel plan against the Giants. They had 9 guys at the line of scrimmage to stop the run and would blitz often. This is not that new, lots of teams try to stop the Giants running game. The thing that the Cardinals did that was a little different was they showed one defense pre-snap and changed the safety's positioning after Eli adjusted the blocking schemes and/or the play call. Lots of defenses do this - show one defense to the QB on his pre-snap read and then change the defense at the last minute. The difference here is that the protection schemes that the Giants change to and the audibles that they make in response to the defense are so transparent and take so long for Eli to call out that when the defense re-adjusts, the Giants offensive play has no chance. This was particularly effective last week because the Cardinals S is very quick and very smart. For example, Cardinals would show 2-safeties back and near the snap, would walk one S up and shift to single safety high. It was too late for Eli to audible to a pass play, but he could change the direction of the running play to the opposite side of the field. To handle this, the S, instead of coming straight ahead, would run diagonally across the field and stop the running play. The play calls are too obvious, the changes that Giants make are too predictable and the Giants made an average Cardinals defense look like world beaters last week.
The announcers of the game seem to have discovered something about the Giants snap count. I don't know if they're exactly right, but it sure seemed like the Cardinals were getting a great jump on each play. This is something the coaches and Eli need to fix because it can make any offense look terrible. In 2000 when the Giants shutout the high powered Vikings offense 41-0 in the NFC championship game, the Giants discovered something on film about the Vikings snap count when they were in shotgun formation. Specifically, regardless of what the actual snap count was from the time that the OL got set, whether it was 1 beat or 5 beats, the C would drop his head and exactly 1 second later would snap the ball. This tipped the Giants when to rush. I can remember one play where Giants MLB Michael Barrow sped around the Vikings RT on a blitz and he was past him so fast that the RT did not have a chance to get out of his 3 point stance and even attempt a block. This is important. I don't think the Eagles are quite as exotic with their defense as the Cardinals were last week, they just like to dial up a lot of blitzes. But they will put extra guys in the box to stop the run and will blitz on running downs and passing downs. Giants have to be willing to take shots down the field and have to be a little deceptive on their formations and play calls.
Another indicator of being out-coached is the failure to make adjustments in-game to what the opposing team is doing. There are a few specific examples of this from the Cardinals game. In the first half, the Giants did a good job keeping Fitzgerald contained. They knew where he was lining up and they managed to get Webster or Thomas on him most of the time. In the 2nd half, the Cardinals lined up Fitzgerald at different spots - in the slot, even in the backfield once and managed to get him away from Webster. They got the matchups they wanted, with Fitzgerald in the middle of the field against a S and made a few big plays.
On the other side of the ball, the Giants had 14 points in the first half, though the offense did have some help in generating these points. One was good field position after a fumble recovery and one was on the lucky tipped ball by Nicks. Nevertheless, they did move the ball during the first half and at least had some plays for these scores. In the 2nd half, the Cardinals adjusted their defensive scheme, as noted above and the Giants did not get a first down on the first 3 possessions of the 2nd half. When the other team adjusts to what you're doing and stops you cold, that's 100% coaching.
Great coaches may have different game plans for the first half and second half. Or they may have a game plan assuming the opponents play to their tendencies and another game plan if the opponents do something different. I don't get the feeling that the Giants coaches go in with that level of planning. Against the Saints, the Giants players said that they expected the Saints to try to run the ball. I guess the Saints have run the ball 60% of the time in the 2nd half of games. (This is probably misleading, because a team tends to run a lot more when they have a big lead, but that's a different question.) Nevertheless, the coaches plan for a running attack by the Saints may not have been unreasonable. However when they saw the Saints throwing the ball all over the yard they should have changed their plan and made some adjustments.
Maybe this is just growing pains for the new DC and an OC that, although he's not new and has been around, needs to get used to new WRs and see what they can do. Certainly, I'd rather see this happening at the beginning of the year than at the end of the year, but the coaches have to show us that they can adjust the game plans before we give them high marks.