Drafting the best player available (which is a relative term, because it relies on the evaluations of the team, which isn't foolproof) isn't always the best move. I'll bet the Titans valued Ben Troupe as the best available at the time, but they would've been better suited using that pick on an O lineman (maybe Justin Smiley or Jacob Rogers) or even a linebacker (like Dontarrious Thomas), something they now acknowledge they really need. Maybe if they had taken Thomas there wouldn't be a need to go after a guy like Derrick Johnson of Texas this year, though they could still look to bring in a CB like Pac Man Jones of WVA, especially after letting Rolle go.