It would give IAG a stranglehold on the UK domestic market, eliminate competition at LCY and LHR and be a great feeder network.
Virgin would be another option but I think they have bigger fish to fry.
CityJet? I know they've changed focus but Flybe might be helpful for them.
Which leaves BMI/Loganair which would be delightful. I've posted my thoughts on their spat earlier.