In what world is Sydney Brown better than Blankenship. No, just no. More athletic, yes, but no where near as productive.
Blankenship is a decent safety, despite what many of you think. Maybe more than decent. Yeah, maybe he gets exposed once in a while if a team schemes a good WR against him, but Fangio is good at making that hard to do. And Sydney Brown would get tuned up twice as much as him in those situations. He can't cover.