The Cardinals were ranked #1, only allowing 2.9 yards per punt return.
I think a bigger impact on Seattle would be eliminating Penalties and Turnovers. The 49ers had 1 turnover (INT) in the game they won 19-17 against Seattle, while they had 3 Turnovers (2 INT's, 1 Fumble (3 total, 1 lost) in the (23-17 loss) NFCCG, and in the first game (29-3 loss) there was 5 turnovers (3 INT's, 2 Fumbles (2-2 lost).
Defensive Penalties vs Seattle in 19-17 win was 3 penalties for 30 yards. While the losses were 5 penalties for 55 yards in the NFCCG, and 6 Penalties for 81 yards in the 29-3 loss in Seattle.
Seattle is opportunistic, and if teams are able to reduce turnovers while also eliminating personal fouls, unsportsmanlike conduct, unnecessary roughness, and taunting penalties, then Seattle would be in a much worse situation every game.
[ Edited by dave_n_ruth on Feb 12, 2014 at 2:09 AM ]