Der Spiegel has just published a full version of Fizazi’s letter, as well as a good article by Yasin Musharbash and Andreas Ulrich.
Upon reading the letter it seems to me that Fizazi is speaking primarily about terrorism in Germany and by extension about terrorism in Europe. His statements do not amount to a renunciation of violence, but to a moderation of his previous views regarding where and against whom violence can be used. By saying that Germany is not a legitimate area of operation, he is implicitly rejecting al-Qaida’s global jihad doctrine.
Unfortunately Fizazi does not elaborate on his views on violence elsewhere. I am speculating, but I suspect he still views attacks on Western targets in Afghanistan and Iraq as legitimate, not to mention the jihad in Palestine. It is not clear what he might think about attacks in the US or attacks on Arab regime targets. While all this makes Fizazi less of a moderate than many would have hoped, it makes his statement seem all the more genuine.