nothing wrong with the scheme
since both the Patriots and Ravens run the 3-4, and ironically have won 3 out of the last 4 Superbowls, I am going to assume there is nothing wrong with 3-4.
San Diego exploited Eric Brown's know weakness in coverage with a physically talented TE. it is the job of the DC and Capers to figure something out to cover up that weakness, but even late when then needed a play they were able to find Gates.
A large part of the offense this year will be to keep the defense off the field and with 4 turnovers, they did not do that.