Not only was their no retention offer, but the phone tree allowed me to cancel my Aviator Red account without any human intervention whatsoever. The phone robot did ask why I was cancelling (increase annual fee, loss of 10,000 bonus, etc.) but it cancelled my account without any human intervention whatsoever.
This did occur after identity verification via touch tone/voice but I'm surprised it was automated to the degree to not involve retention at all. It seems Barclays is intent to let those who want to cancel due to the changes just cancel, even if Barclays can't sign them anew.