Biggest story?
Hmmm. Babcock ended up being the biggest story for sure. It was a bombshell in a way because the Leafs had been written off by the media for what...2 weeks as being in on Babcock? And then they were reporting he was signing with Buffalo the night before he ended up with the Leafs. That was a huge shocker.
But there was build up to the Kessel trade. There were rumours of the Leafs and Pens working on something at least a day or two before, so it got a ton of coverage before it happened.
But Babcock for sure was the longer lasting big story IMO, even though it didn't have the rumour build up.
So I'd go Babcock, Kessel, then Clarkson (which was the most shocking to me this year, more than Babcock! My jaw dropped to the floor when I read the breaking news!!!! The impossible has happened!)
Stuff with Nylander/Marner isn't a big story to me because I had a gut feeling Nylander was something special, like really special and Marner is a great prospect before and after being drafted. They're great stories, in fact the best stories if you're a Leafs fan, but they're not the "biggest" stories IMO.