Who can contribute to a WC campaign and who cannot

The following players can contribute to a better than expected WC campaign:-
Willie le Roux, Bryan Habana, Jesse Kriel, Damian de Allende, Handre Pollard, Patrick Lambie, Duane Vermeulen, Lood de Jager, Eben Etzebeth, Pieter-Steph du Toit
The following are dubious cases for reasons given:-
*  Jean de Villiers - lack of match-fitness after protracted injury problems*  Fourie du Preez - lack of match-fitness after protracted injury problems*  Ruan Pienaar - Slow and predictable - jo-jo performances *  Francois Louw - Questionable performance in recent tests*  Jannie du Plessis - Reasonable scrumming in latest tests - but zero contribution otherwise*  Tendai Mtawarira - Questionable recent performances*  Bismarck du Plessis - Jo-jo performances of late - no consistency
Expected failures - reasons given
*  JP Pieteren - lost pace comprehensively - poor in all matches this year*  Francois Steyn - lost pace and atrocious in performance since return from France*  Morne Steyn - disastrous last three test performances*  Willem Alberts - has not had a decent game since 2013 - regular deficient performer*  Victor Matfield - Non-contributor to Tight 5, reasonable in line-outs, but real problem case in all facets of play as a result of physical deficiency.
The jury is out on all other potential squad candidates.
The above situation is precarious and will in all likelihood prevent us from readhibg th semi-finals,  Present indications are that De Villiers will become a non-playing captain with a few bench selections only,  The rest of the questionable cases and pure failures remain seriously problematic.  
Should they be in the squad - I think not.  The recent massively improved performances of the Bulls showed what can be achieved when a player/coach like Matfield is not around to bedevil the team environment.  The selection of players way past their sell-by date indicates why certain players will not be to the benefit of the team.