Ok, so you want to ignore examples if they don't support your stance?
You didnt specify that it out to a conversion right out of college, so Woodson's fair game.
The fact that you're now talking about someone right out of college instead of a seasoned pro like Woodson, did you think that could actually help the conversion process? If a guy has less "corner" wiring in his brain he might be able to pick up the "Safety" wiring quicker, teaching an old dog new tricks and all.
There's also the ego factor, no one wants to look bad in front of others, and if a guy had success as a corner but switching to safety means he goes through a learning curve where he struggles, he might quit on it for that reason alone.
So, if Troy Brown can go from receiver to defensive back I think the right guy with the right coach can make the switch from corner to safety.