Yeah SD offense was disappointing. They seemed uber-conservative with a lot of short crossing routes that weren't really getting them anywhere. Combined with a couple drops and some typical Rivers Monday Night magic at key moments and you have a very disappointing loss.
Bright side was their defense played pretty well. Let Palmer scramble a bit much and they let Floyd loose, but decent pressure up front (albeit not against an elite OL), competitive against the run game, and mostly shut down Fitzgerald.