Regarding slots and extra services, this what seems confirmed so far for S12 (and earlier for GLA).
JFK: 1 extra daily flight
MIA: 1 extra daily flight (4 joint AA-BA services is a strong frequency advantage over DL and VS)
JNB: Increase from 14 to 17 weekly
HKG: Increase from 14 to 17 weekly
GLA: Progressive increase from 52 weekly to 60 weekly from 30 Oct 2011 and then to 67 weekly from 9 Jan 2012.
Still scope to add a couple of new routes!