Tell me what you ARE doing defensively. Names don't really bother me one way or the other. Ratings change and if you use "practice" to inflate your players ratings or not matters as well.
Sliders matter a lot too. I am currently messing around with RG3MVP's "50/50" All Madden sliders [which really aren't 50/50, but almost are]. With those settings, I have seen ratings mater for the most part. For example, in play now I have been crushing teams thanks to the default 49ers defense and having Crabtree, Boldin and Davis to throw to.
However, in the CCM I just started, in the pre-season I beat the Broncos 21-7 and then got decimated by the Chiefs 43-14. Once my back ups started coming in [as it was preseason] my defense couldn't shed a block or make a tackle to save their jobs. Colt McCoy was very erratic and so were his targets and the O-line protecting him. I was getign a lot of pressure nad no one open. When they got open, either McCoy would throw a terrible ball or they would drop it [twice there were drops that bounced and turned into interceptions]. There were really only 3 palyers that contributed. MLB #57 [forgot his name right now], DE/DT rookie Tank Carradine and OLB rookie Corey Lemonier.
I do have to ask, what did you do with Corey Lemonier? He has always been a stud for me. In fact, while I am a fan of Aldon Smith in real life, I haven't ever gotten much production out of him in Madden because pass rushing from the left side [defensive right] is a joke. In my current CCM, I actually traded him for Richard Sherman to se for fun if Sherman could help my team at all... and to see what an elite CB can do. I know what Aldon can do for me, and that's almost nothing. A waste of a 99 OVR palyer. Especially when Corey Lemonier can run stuff and cover well enough on his own.
As far as plays go, I do the following:
Against a standard 2WR formation [it tells you what package the offense is coming out in in the play call screen] I tend to call cover 3 plays that have one of the safeties in a blue flats zone. That will stack 8 in the box. I also tend to call a lot of blitzes from Cover 1 and Cover 3. I need to stop the run and try to pressure the QB.
Against 3WR formations, I will either stay in my base defense and call zone, or move to the nickle. the two nickle looks I use with SF are the 2-4 and the Wide 9 with the "LB Pass Rush" formation substitution. The problem is, that the AI, much like real life, tries to play the numbers game. They spread you out with 3 wide and run the ball on you. in the 2-4 you have 6 against 5 linemen and a TE. If every one gets blocked, you don't have anyone to tackle the ball carrier. That's why I tend to stay in the base formation but call things like cover 6, cover 3 buzz, Cloud 3, and cover 2 sink. Those plays keep 7 up front and I trust my LBs to cover in zone well enough. If I do go nickle, i tend to go back to the Cover 3 that has a safety in a blue zone so I can "stack the box" with 7 and keep playing the numbers game.
In the end, for me at least, it still comes down to execution by my AI players. I try to stay simulation style. I tend to user control Justin Smith, Ray Mac, or Tank Carradine. I like to time the snap and flick the right thumb stick down and hold it so they will bull rush. That tends to help by collapsing the pocket as I wait/hope for another defender to get free. Power move defensive linemen are very important to me because of that. I love that animation and the impact it has. The computer controlled pass rush can be very weak without the user helping. They just stand there and play pat-a-cake with each other.
Below are some picture from real life and then screen shots from Madden with his 3 sacks against the Broncos. Against the Chiefs I lined him up at ROLB and he performed no better or worse than Aldon Smith. The LOLB/LE is simply far more effective at pass rushing than the RE/ROLB in Madden. Sad, but the truth.