The folks at Pro Football Focus ranked all of the rosters in the NFL (In$ider). For each team they listed the 5 best players and the 5 starters that should be upgraded. They listed Jurrell Casey, Derrick Morgan, Kendall Wright, Delanie Walker, Jason McCourty as the Titans best 5 players. That's a pretty good list.
The 5 starters they listed that should be upgraded are Justin Hunter, Brian Schwenke, Byron Stingily, Coty Sensabaugh, Michael Griffin.