I have to side with Oraeon on this...spent a good hour today testing pass blocking slider.
From 0 to 50 to 100, I saw really no changes at all for the CPU.
I was Carolina controlling Greg Hardy up against the 49ers (Joe Staley). Pretty even match up.
I was able to get past him with the exact same success rate at every level. In my opinion, CPU pass block slider is completely broken.