MB recommends I read this piece by Archimandrite Grigorios Papathomas:
OUR 'POST‐ECCLESIOLOGICAL' AGE (pdf) [alternative link]

Related links:
Our 'Post-ecclesiological' Age Koinonia
pastoral mission by F. Papathomas
Solidarity and Justice in the Baltic Countries

Canon 28 of the 4th Ecumenical Council – Relevant or Irrelevant Today? (alt)