I'm wondering if we need some discussion about inclusion in this category. I mean, are the Old Believers heretics or merely schismatics? There's an important difference, right? Typos may be heresy for writers, but I'm not sure they count for other folks. Ecumenism may well be an ecclesiological heresy if it means the branch theory, but is this really what most Orthodox mean when they speak about "ecumenism"? (Usually it seems to me to mean something like "talking to other people".)
I suspect for some of these things Category:Disputed issues might be more appropriate. Otherwise just about every opinion in church life will end up being framed as heresy!
Maybe we should restrict this to classic heresies? Or someone should attempt a definition of what "heresy" means. In fact, I think we'll have difficulty keeping things neat and clean here...
I'm just worrying aloud, but does anyone else have suggestions?