Potential flaws,
1. ILB in case Z Thomas gets injured.
This scenario is not especially far fetched.
2. Consistent pressure and performance from our DL.
I'm sold on Ratliff, but both Spears, Canty, and Hatcher need to keep improving (which they should). Also, we'll have to see how Tank comes along, and he's a pretty big piece of the puzzle with respect to the DL.
IMO, our DL is not as good as the Pats' front, for example, though I do like our LBs and Secondary more - assuming we stay healthy.
I'm not saying that our front 3 aren't going to take the next step, but rather that I'd like to see them take the next step before I feel comfortable proclaiming them a top 5 defense.