People are fearful and don't like change.
It's a really great question, and it may have to be answered, no matter what anybody says.
I go back and forth terribly on this matter. One day it would have to be Vontae because he is a way better tackler and he got a 33 on his wonderlic and just seems more aggressive; but the next day I think Sean Smith with his height and long arms would just menace opposing passing attacks.
The only thing I am sure of is this: Sean Smith is on the record saying he likes the idea of playing safety very much, but is fine playing either position.