Well, to be clear part of it is that Ange himself managed to clear all of those hurdles despite varyingly long odds of doing so. I think retroactively considering our run through the competition as an easy and likely accomplishment is wrong.What is it that we would have lost that they wouldn't have been able to replace?
But I do think the chances would have been lower under Mason, whose skills I don't have a ton of respect for as a 33-year-old who has never properly taken charge of his own team. I hope he gets the West Brom job and can begin his career in earnest.
To answer the question though, I think both the consistency of message and principles under Ange helped us through the competition, and that he did offer some ineffable nous about getting through those crunch do-or-die moments. He instilled a steely mentality in the knockout stages that his more decorated predecessors couldn't.
Both the guy who whipped Spurs into a mentally strong winner in European away legs and the guy who lost at home to Ipswich on the road to a 38 point season are the same guy. It's a funny old game.