I have to agree with Finochio, I found it unsatisfying as well. I was good to see how Michael spent his last days. With all of Vincent's manuvering to be on Michael's good graces, I thought is would be more interesting to know how Vincent felt about being Don. Was it worth it?

Michael had a type II diabetes for a while, one of the complications of that is slowly losing your eyesight. I believe most people who goes though this type of blindness have eye pain when exposed to direct sun light. Dark glasses helps. We see Michael wears glasses when he is outside on a sunny day.