Nencini's post-verdict remarks - if reported correctly - appear to show the root cause of the convictions. They also appear to have massive relevance to any upcoming ECHR application.
What Nencini appears to have said is along these lines: the SC tells us that two other people were involved in the murder (in addition to Guede). We (Nencini's court) accept this unconditionally. Our job was therefore to establish whether these two other people were Knox and Sollecito, or whether there was credible evidence of two other people being involved. If we had decided that two other people (i.e. other than Knox and Sollecito) were the two other assailants, we would have had to show compelling evidence to support that hypothesis. We had no such evidence. We could only therefore conclude that the only reasonable conclusion is that two other assailants were Knox and Sollecito.
If that's a correct interpretation of Nencini's remarks, then it looks like exceptionally strong grounds for a successful ECHR application right there.
As more becomes known about how Nencini's panel of judges/lay-judges worked, it's not only this. I believe you are correct, that Nencini instructed the other seven panel members on what the ISC stipulated... so that every time the defence brought up the unlikelihood of multiple attackers, Nencini and the other seven would go back and say, "well, they just wasted our time - we've already been directed to find multiple attackers."
There's more. Now, all the caveats need to be put into place about Nencini talking to reporters... like Hellmann in the days following the acquittals.
Nencini also reports that one of the lay judges came to him quite confused. She was being confused by everything she was seeing on television.
WTF!?
Now before Machiavelli drops in to give us a lecture on the role of the lay-juror, apparently they are there to vote with their feelings and overall "osmotic" sense of what this case is about, complete with conversations over dinner with family, coffee with friends, and perhaps even what the priest says about the case at confession. I guess in this way the lay-judges "represent the community".
This is what is so hard for North Americans to understand. In our system, this would have got that woman kicked off the jury. We have sequestering, we have instructions to refrain from discussing the case even amongst fellow panel-members until the cases have been completely rendered.
Yet here, at least according to Nencini - meditated through a newspiece so all cautions should be in place - a juror is basically asking, in my mind, how she should vote.
Given that Nencini also hedged on if this had been a unanimous verdict, there's this nightmare scenario that this was a 5-3 vote. Do the math on that one.