The brief we got at BA is that it is a merger not a takeover so the two companies will continue as they are. But who knows? I guess it might be run along the lines of AF/KLM.
I would envisage a whole load of job cuts on the ground. It would cut out the need for job duplications.
As far as flying goes I can see BA only operating as far as BKK/SIN/HKG and Qantas doing the flights down to Ozz.