This being a very long tread if someone could enlighten me I would be grateful. For those who think NCC-1701-A was a new ship, how can we explain her decommissioning only after eight years? This is one critical fact that makes me doubt she was a new ship...
My guess is that the Excelsior finally proved herself and the 1701-A may have been part of of a batch of ships that were started then left unfinished or the A may have been a final ship but left unfinished due to the Excelsior. When Kirk and company returned and saved Earth the ship was quickly finished and rushed into service to give to Kirk. This quick rush job may explain the multiple "bugs" and the Excelsior may explain the early decommissioning.