Wonder how EIN managed it the early 90's with their old 747-100's fully loaded to JFK
Me too. EI operated their old, poorer-performance -100s out of there for probably 25 years, from long before 10/28 was even built. 16/34 is only, what, 75% of the length. And I seem to remember seeing one in Tenerife on an IT charter from Dublin, so it wasn't just the Shannon hop that got out of there.
And what about the Aer Turas stretched cargo DC-8s ? They seemingly had no problems either.
One for the performance enginers of course but surely better-performing aircraft and a longer runway must give some benefit.