2 things that can fix defense
-Line and Linebacker Gap control with different fronts within the 4-3 and 3-4. That way everyone has a responsibility and its not just like... okay... get set... now tackle the guy with the ball.
The second things that I believe will fix this is that they need to up the awareness of Defensive guys just a tad. I know they cant make them that smart and in tune with whats going on becuz people would complain about not getting much offense. What they should do is increase awareness all the way around. Defense needs to react to the ball all the way around. Have tendency ratings that determine whether or not a defender is likely to try for a jarring hit or if he would rather go for the ball. On offense we already have a Catch in traffic and spectacular catch rating so lets do something on defense to off set that more than just having a hit stick.
One more thing for defense. If a guy is running the same play over and over again.. especially in the same type of situations, make the defense more likely to catch on. If Im a corner and my man runs 15 yard outs more than 50% of the time, Im gonna start jumping that route.
Oh yeah... add two types of cover 2 zones. Hard and soft. Hard cover 2 the corners jam and play strongly in the flats. In a soft cover two they back pedal off the line and they'll play anywhere from 7-15 yards deep just to keep everything in front of them. Also, The safetys in cover two need help. In NCAA everyone just goes to a certain area which is not true in real life. You have responsibility of an area, but the opposing offense dictates how fast you get to that area. God, I hope the right people are reading this.