Yikes. These Trouba proposals are always the same old song and dance. Someone starts with a lowball offer by Toronto to get Trouba (this one isn't necessarily as bad as some of the others, at least Nylander has some value, it's just that the Jets don't need forwards.) Then Jet fans come in and say the asking price is Rielly (because it would take a quality piece to bring in a young, skilled, top-pairing potential defenseman who is already a top 4) and then Leaf fans whine that Rielly is much better/Trouba wants too much money that he doesn't deserve/Trouba's overrated and not good even though they just proposed a trade for him.
As for the original proposal, the basis doesn't work for the Jets because we don't want to trade the most valuable piece from our weakest pool to improve our strongest one. We already have a logjam of talented forward prospects; so much so that it may result in Stafford being traded. Would you trade Rielly for Connor? Because that's what that proposal is like to us.
I can see why the Leafs would do it. They're essentially trading the least valuable of their big three prospects for a stud defenseman. I would have to think the asking price for Trouba would be too much for Toronto.