Thank you for all of your hard work Michael! I don't agree with the conclusions that you've reached but I recognize that one viewpoint is just as valid as the next. Here is mine. There are many different modeling message boards. The ones that I know of that deal with scale aircraft and are in English include Hyperscale, Large Scale Planes, Large Scale Models, Scale Plastic Aircraft Modeling, Finescale Modeler, Aeroscale, International Scale Modeler, Britmodeller. All of these have group builds and participation in the group builds varies on each of these sites varies. What differentiates WW2aircraft.net from the others, in my mind, is that it focuses on aircraft from WW2. Yes, our interests often extend to other eras and other types of models but I think the calling card of this particular site will always be WW2 aircraft (literally, since the website name is WW2aircraft.net).
So I have no problem limiting the GB topics to WW2-based themes. That's what I'm into, personally. Yeah, I'll do the occasional jet or sci-fi build but my passion lies in WW2 aviation. That's why I came here. I don't mind repeating themes because there are hundreds, if not thousands, of subjects to choose from each theater of the war and there will always be an interesting aircraft for me to model. Based on my limited experience in the group builds here and browsing through the group builds of the past, it seems like the strongest participation is generated by WW2 themes and I believe that this will continue to be the case. Based on past history, I don't think that the non-WW2 subjects are popular here and incorporating them into the GB's will serve to limit participation, not increase it.