I agree with you on every point you make except one – that both the Giants and Bengals had good game plans. The Bengals coordinators were way ahead of the Giants, and the Gmen are fortunate it didn’t cost them the game.
Gilbride kept trying to establish Jacobs and the run against a team that was determined to deny this part of the Giants game plan, and the Giants O started flat and never really untracked until late in the game. Meanwhile Spagnuolo kept recklessly sending blitzes (even though they were getting good pressure on 4 man rushes) which got picked up and exposed the secondary, especially in the second half. I’d like to see a little more aggressiveness from the O and a little more caution from the D