IMHO Super Stall has it right:
They hold all the cards this time. They don't need to offer anything in return. Sometimes they just have you over a barrel.
Sadly for the potential new joiners that's exactly how I see it.
Firstly IAG don't need to offer BA pilots any say or input at all, so I'll credit BA management for at least trying to give the impression of trying to engage with the current pilot workforce.
As for the ballot on the deal - if the BA pilots vote "No" IAG will simply set up a separate OpCo to exploit the LHR slots (called "Jetstar Europe" perhaps ?) and BA mainline withers on the vine.
Then we have the calls for a strike, aka "showing some backbone", "growing a pair" and all the other colourful rhetoric? Anyone who has followed recent IR history in the UK will know that the courts would almost certainly side with IAG/BA in a dispute over this and regard Industrial Action as BALPA attempting to tell IAG how to run it's business, rather than a genuine grievance over existing employees T&Cs. Do we want a pointless and very expensive repeat of the Openskies fiasco?
It's not a perfect deal, I'd like to see a lot more detail, but I fear it's the best available and at least for the forseeable future ( however long that is) there's a BA worth joining!