I personally have been told by very senior people at BA haw amazed they were at the success of AF/KL, having been very sceptical about how two such different corporate cultures could be brought together.
Indeed. BA has admitted that prior to the AF/KL deal they had focused on what mergers can achieve in terms of cost saving and what impressed them about AF/KL was what was achieved in terms of revenue synergies and that is where most of the benefit in the Iberia deal will come from - driving traffic and revenue into each other's networks and co-ordinating schedules and routes.
It was a pity that BA did not merge with KL as it would have given it a second hub nearby and maintained BA's presence in the regions. In truth, BA now means very little to a lot of UK pax outside of London and the South East.