The functionality we really want is a new array tag field in WorldInfos that allows the mod creator to allow/disallow specific religions based on map size (Or alternatively an array tag in ReligionInfos that allowed the specific religions to be set to specific map sizes). This way the modmaker could add as many religions as they want to their XML and fonts; balance the number of religions, and when they emerge to map size, and it would allow scenario makers to use any religions defined in the mod's XML. A win-win all around. Afforess looked into this but abandoned the work on it; he has a pretty full plate. I as well have a full plate, and also this seems too complex and above my pay grade to implement. However if such an array could be set up, with the ability to specifically set certain religions (or rather the tech in which those religions emerge, as "choose religion" would allow the user to change the automatic religion by that tech if that gameoption was enabled) to specific map sizes, then adding a larger religion modpack to the core of RevDCM and to it's derivative mods would be more viable.
Edit: Actually now that I think about it and browse through the SDK, I think it's very possible to set up a mapsize array in ReligionInfos, but I wol't be doing this until after the release of 2.7.