Didn't Jesus make it clear enough when he in conversing with the Samaritan Woman at the Well that there is no longer need to go to a geographic locale since Worship will be in spirit and in truth  ? 
If ad orientem is so essential in the life of the faithful how come there's a woeful history in Christianity of war , torture ,  all kinds of destruction etc .  Facing the east has not accomplished anything yet .  How essential can it be ?  
I am renewed by this stand taken by Francis  .  He is rebuilding a church which  is in ruin.  
Praise God .