Everybody knows the value of witness protection, but nobody knows the kind of protection that both parties can implement, that is, preparing examination in chief and cross examination and continuous closed session. That is a means of protecting witnesses and protecting the rights of witnesses and using witnesses in the manner that is kind of different. You cannot use other evidence the way you use witnesses.
There is another issue that may be interesting. In the ICTR system, we have had experience of ^proofing a possibility for the parties to talk to the witness before he gives his evidence. So this is impossible in the ICC system, and that may be a problem at a point where a witness protection may also be a challenge.