Hey I am MasterRWayne and I help write for www.stampedeblue.com which is the blog here for the Indianapolis Colts.
I really liked the article posted yesterday discussing that the Saints really didn't have any true defensive philosophy or identity. This, I feel, is really hurting your team. The Colts run cover 2 and cover 3. That is what we are and that is what we practice. Its not a very advanced scheme, but it works great because we know exactly the types of players we need to draft for it. If you wanted to can read my article about the advantages of Cover 2 here...
Basically almost all of your defensive problems come from a lack of scheme and this is exemplified in Jason David. When Jason David played for the Colts he was very very good! Yeah you may think I am crazy, but trust me the guy won games for us. In fact, I remember one game four years ago where it was a high scoring game between the Colts and the Packers with the Packers driving for a game winning touchdown. Farve threw a 15 yard pass to Javon Walker and Jason David (who was a rookie) stripped the ball and recovered the fumble thus ending the game.
This just shows that Jason David can be a very good player when he is in the right system such as Cover 2. The system you guys run just has him confused out there. He doesn't know his assignments and after playing Cover 2 for so long the guy just can't play the system the Saints run.
If you want my advice you guys need to have a system and a philosophy on defense because that can make ALL the difference. Eight years ago the Colts had one of the worst defenses in league history and then Tony Dungy came and we switched to Cover 2. We made an effort to draft faster, smaller guys that fit into our system. Currently we drafted a guy named Marcus Howard at the bottom of the 5th round and he has FOUR sacks his pre-season and is amazing. The reason we got him in the 5th was because he was "small" and other teams wouldn't touch him. Its the same reason we got Bob Sanders (last years DPOY) in the 2nd round because he was "small" at 5'8.
Bottom line is you guys need a defensive system that compliments your quick strike offense and Cover 2 can do that. By scoring fast and effectively with your offense it forces teams to throw the ball in order to catch up which in turn plays into the strength of the Cover 2's speed rushers and zone coverages.
Anyways I wish you guys the best of luck. In my 3 Man keeper league this year I thought about keeping Reggie Bush, but decided instead on Larry Fitzgerald. I am just not sure if Reggie has it, but feel free to challenge me on that or on my knowledge of NFL defenses.