I fly the Airbus (and I suppose I am a fan) and our SOP is packs off for all take-offs which is nothing to do with asthmatic performance but $. It's to save money because there's less demand on the engine hence slightly lower hot end section and therefore extended life / reduced maintenance cycle. When the aircraft are performing perhaps 8 take-offs per day on with a 200+ fleet small savings soon mount up.
Putting packs on after thrust reduction is a complete non-event, just leave 10 seconds between the two to prevent any surge. If you forget you get an ECAM caution displayed telling you in plain English that you have "PACK 1 OFF" "PACK 2 OFF". (You don't get the take-off CONFIG warning at 10,000+ feet when á la Helios.......)
Perhaps you misunderstood my post. I said that GLA-ALC would not present any performance problem. I was merely trying to establish if Jet2 did bleeds on or off - not which aircraft has the better wing..... (In reality, I bet there's a fag paper between them).
I think the crew did a good job by all accounts. The final report will be interesting.