Mike Wallace needs to be the #1 target. He's exactly what this team needs. Even in what was a down year for him, Wallace scored 8 touchdowns and his speed opens up the running game. Miami can look for a physical receiver in the draft and have a nice unit going forward.
As to Sean Smith, I don't know if he's even an average corner. I do think he still has some upside, but if his salary demands start climbing above $5 million a year I wouldn't be too quick to re-sign him.