I didn't not agree with you in terms of MAN and 2nd DUB, I'm reserving comment on that front
I understand that BOS did quite well, the loads regularly surpassed the 757 capacity from what I hear. The reviews were quite poor though and from what I understand the 4th 757 will do an early morning JFK from DUB next year, therefore removing the need for the 757 from Shannon. Hence I can't see the 767 returning.