Bell missed a few tackles, but remember how wet it was... a lot of defenders were slipping. When it's wet, it's always more of a disadvantage to the defense in terms of open field tackling.
Also, I thought Bell showed impressive recovery speed. He was beat by L. Coles I think on one play, and recovered, but was called for a questionable pass interference play. On the touchdown he gave up, I think a lot of the credit has to go to Pennington. Bell was underneath, and had help over the top and Pennington put it right on the money. If the ball was thrown a couple inches shorter, Bell would have defleted it, maybe even could've gotten the pick.
Bottom line, Bell in my opinion is a future star at safety. Yes, this is his thrid year in the legue and he's already 28 years old, but he's never gotten as much playing time as he did this season. This season meant a lot to him in his development, and I think he'lll only get better. He seems to have all the tools. I would think a lot of Dolfans would agree.