Just a few thoughts... The parish I grew up in built a new Church in the Early 80s that represents the modern church architecture being defended here, and the current church I go to was built in this style (and remains in this style despite having some wonderful priests).  At the very least, moving the tabernacle from behind the alter is a source of great confusion.  Ultimately people tend to genuflect towards the front of the Church, and when the tabernacle is moved to one side, it means we are genuflecting to the alter, not Christ.  In addition, the more extreme versions of Church in round are not very functional for facilitating communion.  The very long pews that wrap around make it difficult to easily get to an aisle to move forward to communion.  As something that seems trivial, but perhaps not, the short central aisle (assuming there is one at all),  I suspect has convinced more than one couple on the fence about getting married in the Church to go somewhere else.