I couldnt see IAGs involvement putting an end to TA expansion, as the void would be filled quickly by US carriers. Moreover, there are opportunities to grow interlining traffic ex Europe, from many airports that BA do not provide service to as well as from some UK airports.
EI offers nothing to IAG other than the Heathrow slots.
JAS this is precisely what I am saying, heathrow slots, not those of EI, but their own slots, releasing 8 daily slot pairs to the BA network could result in 8 new long haul routes as a daily frequency which is a serious expansion. Depressing traffic on Dublin USA would also drive demand for more slots for LHR DUB....
Watch this space.