Apart from the small matter of over 10000 crew existing terms and conditions, that do not appear to align with future working patterns. BA are 3-0 up, but it is only the start of the second half.
From BA's perspective, there's very little left to agree with the unions. It has got most of the savings it required from Mixed Fleet and crewing changes, neither of which are going to be reversed. The other issues such as changing the disruption agreement are relatively minor in the grand scheme of things.
BA has never anticipated making major changes to existing crew t&cs.
Also if Unite don't accept the current offer, crew don't get two consecutive annual pay rises.
BASSA will never admit it but it is game over.