Napoleon wrote:@Ottoatm: Woah, last I checked, there are many more Christians than Hindus. Also, he might be refering to every denomination, and not just Catholic. I, as a Baptist, still take offense if they make Hindu/Bhuddist/Islamic temples/churches, and yet have not made a Medieval Catholic church. Fine, leave the crosses out, but please, LEGO, make a monastary.
When ottoatm said there are more "hindus, muslims, etc" he probably referred to the fact that there are a lot more non-Christians than Christians in the world (as if Christian would mean one thing only for that matter....).
I for one find the whole idea of getting offended at a set of any kind of religious building quite alien but I do agree with those who think a monastery without symbols would work best. I would love to see a monastery or convent anyway, then again, as pointed out, I could build one myself just as fine.
As for the topic at hand, what I'd think this gap (what gap by the way?) needs to be filled with... I can think of a lot of things but to be realistic it'd probably have to be quite fancy and violent, so why not something truly different in that way? Floating castles and airships? An "evil" faction of human (perhaps allied with trolls or what-not) sky-pirates facing some avian kind of people with wings for arms or so.