Rob was a TB in high school and a RB at Syracuse neither of which required the lead blocking skills he now needs. His first year with the Dolphins (1999) he did not block well. He worked hard on improving, with special technique (required because of his 6' 3", long waisted frame) that Joel C. worked with him on to help him get leverage. The concept was to make, and retain, contact and seal off - as opposed to going for the pancake block that "bowling ball" FBs can do. He became fairly effective at it - good enough to hold off Dyer in Chan Gailey's FB blocking system for two years. In Norv's system he blocked for Ricky and RW put up big numbers. Despite how we all feel about RW now, he was a top running back and he personalized a photograph for Rob that said "You are the wind beneath my wings". Hardly sounds like he thought Rob's blocking sucked. There was a full article in one of the Miami papers a year or two ago on this exact topic, much of which addressed some of the things I have commented on here.
Personally, I don't think Rob's blocking could ever be compared to a Gash or Neal, but it is nowhere near as bad as you have stated.
Just my opinion.
PS: Upstate NY rocks!