The only team that needs 6 players for one position is Arsenal.
Barca needs main XI world class players (which we already have) and great players who can play in a variety of positions (which we already have - Turan (CM, AM, LW, RW)in a month), Rafinha (AM, CM, RW, LW - injured), Sergi Roberto(DM, CM, RB, RW), Aleix Vidal (RB, RW), Mathieu (CB, LB
), Vermaelen (CB, LB?), Bartra (CB, RB
), Samper (CM, DM), Munir (yeah i know), Sandro (still know), Adriano (again, i know), Douglas (GK,RB,CB,LB,DM,CM,AM,W,ST;Manager,Ref,Linesman,Club President,*Mascot*).
A player who can be effective as a replacement for Suarez is needed but who can also play on the wings. And the other area is LB, as Mathieu, Verma and Adriano really aren't that great at the position. And I understand people who says that next summer we need to freshen up the CB position. But when thinking of present time, I can't really complain about the squad.