Retention of a Player: Part of The Raiders’ Problem, or a Good Thing?

When doing a little scouting for information, I came across this little article regarding turnover rates for players and the ability to retain players:

http://espn.go.com/blog/nfcwest/post/_/id/18906/where-every-nfl-team-ranks-in-turnover

It showed the Raiders sitting at 12th overall, with the team keeping 83.1% of their players from last season with the club.

Now some of this is pretty understandable...a team that is drafted and built for the long haul does have the advantage of knowing what sort of player is next to you. Does this guy run a good deep pattern? Does the Tight End make decent catches? Does the Corner know how to blanket a WR streaking downfield?