Hi Liefern (?),
I'll try to comment and answer some things.
"It can be seen that a plausible argument can be made, for not putting too much store by either calendar. Calendars are a bit arbitrary, and unity of calendar has sometimes been thought unimportant, i.e. not a reason for condemnation. Perhaps when they have been the source of condemnation, it is more that the calendar is a proxy for other issues."
There is some truth in this. There have always been different dates for some festivals, though, this never largely amounted to a totally different system (for example, different dates for St. Catherine's feast, and a few others). However, as you observe, the Calendar introduction was part of an whole set of packages that intended to introduction additional things (like the ecumenical heresy, etc). The Julian calendar was itself set for use by the Nicea and subsequent Councils; to change the Church tradition on this matter would, AT THE VERY LEAST !!, requiring an Ecumenical Council! But, then, why do that, when so much else is important? If you read the Ecumenical Patriarchates intent for introducing the New Calendar, you will see that it was set for the reason of liturgical-prayerful unity with Protestants; this is a very bad reason to begin with. While we have protestant family, etc, we cannot have prayerful unity with them; instead we wish them to become Orthodox. Additionally, up until the anti-canonical Calendar change, it was widely admitted that he act of rescinding the Julian Calendar was itself tantamount to initiating a Schism (the first New Calendar Archbishop of Athens, before becoming Archbishop, admitted this in 1919!). It's introduction has proven profoundly disastrous in Greece, Romania, etc. Admittedly, there have been occasions in which some places have used the new calendar and these were Churches we would acknowledge to be True Orthodox (for example, ROCOR did participate, unwisely in retrospect in the elevation of the New Calendar Patriarch of Romania in the 1920s; and ROCOR, did allow some of its parishes to use the new calenar and even one of its Bishops, but, these were unwise decisions, and later sources of unneeded controversy).
"It may be that today, the Julian calendar at least reduces the field somewhat. Orthodox on the old calendar are not necessarily free of heresy and problems but at least it's a start. After the WCC is surely on the new, right? Do you see it that way? Or do you think the Calendar itself has an important essence?"
Yes, it is a start. The traditional Church Calendar (Julian) shows where to begin looking, and the field begins to narrow from there (does the Church refuse communion in prayer with non-Orthodox and all other liturgical actions, does it derive its Apostolic Hierarchy from either ROCOR, for starters). The Calendar can be said to be important in 'essence' because of what it symbolizes; it would be as if a Local Church decided to abolish, wholesale the prohibition on married bishops, it would be such a radical departure as to merit drastic action!
In Christ,
Fr. Enoch
