Currently, I'm working on recruiting interviewees. Initially, I was thinking to interview first people as developers of BfW and later on, people as users. However, I realised this was a bad choice at two levels. A practical one: the whole process of interviewing one group at a time could result in delays (e.g. If I have to wait 2 months before I complete developers interviewing without even beginning to make questions to users I can end up having some problems when unexpected delays happen.). At a theorical level: it is somewhat artifical to distinguish informants' categories between "developers" and "users". They are both at the same time.
Anyway, I currently sent reruitment calls in the international community (-dev mailing list, #wesnoth-dev) and in the italian community forum, and I'm really satisfied by the answers provided by the people. They showed supportive about my research and provided some useful clarifications. For instance, I overlooked the fact that artist developers are far more present within the international forum than they are in the mailing lists and IRC.
I definitely need more people to interview, but I'm sure that with the few ones who already offered their help, I can let emerge some good hints about development/use mediation in Wesnoth.