I didn't say it was a panacea, but the increasing shot blocking will make a difference. You have to remember due to injuries we were playing small at virtually all positions 1-4 last year--providing countless mismatches requiring doubles and overcompensation. Sure the defensive intensity and focus need to be turned up a notch (quite a few) in addition. But don't underestimate the impact of Ming and continued development of EG in impacting team D. I do think if could get a SF like Russell (if Lewis is out of the picture) that would help solidify rotations and perimeter D.
I think we now have more capability to intentionally play a defensive scheme. Without injuries we can put together combinations to shut down the other team depending on their strengths. Look at the "new" guys we will have now, MT - 6' 10", Rice - 6' 9", Ming 7' 6", and Nachbar 6' 9". With additional experience and training camp together, I think they can make a big improvement in this area. I look for Griffin to be much better just due to growing physically and being better prepared for the NBA mentally (experience).