In terms of game mechanics, the debate over semantics is, well, semantic. The proposal as I understand it and support it is to allow an Elder to create a subgroup within a religion that we can think of as a variant form of worship that is still recognized as being part of the parent religion and continues to operate under the same hierarchy.
For roleplay purposes, the actual differences that separate this group from the mainstream faith could be literally anything - overemphasis on a specific god within a pantheon (like a Cult of Apollo or some such), differences in worship practices, even doctrinal differences such as whether or not to accept the infallibility of a certain spiritual leader (*cough* Sanguis Astroism *cough*). Naturally, in some cases we could expect these differences to lead to a schism, but they do not have to, they can simply be used to create greater diversity within a faith and enrich the experience for all members.
Here are my thoughts about the actual mechanics:
*A member (including priests) could visit any temple in order to affiliate or unaffiliate with a sect (which is term I am choosing to use to describe the differentiation).
*Lords could choose to dedicate, rededicate, or undedicate (return it to the mainstream practices) a temple in their region to denote which form of worship is practiced there (i.e. which sect controls the temple).
*Within the religion, peasant worshippers could be converted into sects by priests of that sect, by the dedication of temples to that sect, and by being ruled by lords of that sect. Almost a religion within a religion, though to outsiders it all looks the same.
*Non-members cannot see distinctions of sect on followers, priests or temples. It all looks the same from the outside.
*A sect would be able to schism, creating a separate religion and taking all members, peasant followers and temples dedicated to it with it.
The schisming part is still a little tricky. Who can do it, and when? I would lean toward any priest of the sect could initiate one in the manner of a rebellion, but then noble members of the sect would still be allowed to choose whether or not to remain under the umbrella of the mainstream faith. I think a countdown of days would then begin during which members could choose to stay 'loyalist' or go 'rebel'. Temples follow their lords. Common followers would require some other kind of mechanic. Once the countdown finishes, all 'rebel' nobles and temples leave the religion and become part of a new one with the schismatic priest as its founder.
