Just to pick up on some of the points raised:
1. However sensible/fair you think the court's "Without Prejudice" rule is, it was clear prior to the formal rules change (and particularly so prior to Scooby Doo) that (a) people did not understand it and (b) it was being abused. Something had to be done, and of course I am open to the idea that what was done was not the right thing - although the fact that this topic seemed to drop off everyone's radar for two years was a hint that what was done was not bad.
2. The Court's 'without prejudice' rule has some difficulties, in that documents marked "Without Prejudice" aren't necessarily covered by it, and documents that have no such markings can be covered by it. It would probably be interesting to see if anyone (and I suspect that Beasty has the best chance of doing this) can write a (a) brief, (b) simple and (c) easy to explain to a layman explanation of W/P that could be applied to the DRS. I'm sure it can be done, but it might help us all to see a draft.
3. Just to clarify something that was raised above, a document is not necessarily "Without Prejudice" just because one party thinks that it isn't/shouldn't be (or it wasn't generated by agreement). Having said that, it clearly helps (as in everything) if both parties view correspondence in the same way. In the courts there can be separate hearings before a judge about the W/P status of a document. Even if W/P did apply to the DRS, the expert would still have to decide whether a particular document was, or was not, genuinely W/P - which is not significantly different from where we are now.
4. If you settle a case without coming to the DRS, then the issue of whether the DRS would be prepared to look at those documents is moot. If you are having genuine "Without Prejudice" conversations it is open to the Expert to treat those as genuine and ignore them.
Finally, I'd be interested to hear about any cases where this has been a real issue with this.