Nope, not placing the blame on CB. I understand his approach, however, it doesn't change that this team will once again have to rely heavily on Luck this upcoming season, due to lack of defensive talent.
IMO, adding Sheard, Simon, etc... adds depth or starters to our D, which is a good thing. I don't think they will be difference makers, and thus, we still have the same exact holes to fill. There were starter level FAs available that we could have targeted that would have filled some holes (CBs, ILB etc.) for the long term. As it stands, we still have so many holes to fill because signing low level players does not effectively address those needs. We will eventually have to find high-level players at these positions.
This of course is my philosophy. There are more ways to reach the same end goal and I hope CB's approach is the right one. Besides, what do I know? I'm just a fan.