Yes I do block in the back at 51. It gets called a lot at 51, but I find that it helps balance yardage and scoring with 15 minute quarters. It winds up giving you realistic stats, while also limiting scoring. Penalties are part of the NFL, and this is a good one to have called more frequently in Madden to help even things out. I'm not sure if that makes sense. I like the extra wrinkle that it adds in to the equation. I have considered moving it to 50, and I may at some point, but for now I'll leave it at 51. Just to reiterate, you do see a ton of these called at 51.
As for roughing the passer, I have it at 50, though after reading through your personal set and reviewing the other figures in the game, I'm considering an increase to 51.