There is without a doubt the Leafs have been better the Jets this year.... the "challenge" they're likely to pose is twofold.
1. Realistically, they can "improve more" at the deadline than we can. You look at the Jets lineup, and they have some things REALLY figured out (#1 goalie, top 6 forwards, high quality, gritty, big 3rd line); and some things that are a bit of a ####show (their D). The thing with defence though -- there's only 6 of them. If they go out and get a Josh Manson or David Savard, that could be a huge difference to the overall quality of their game. Identity-wise, they would fall into a very traditional playoff-hockey mold built from the net out.
For Toronto, the holes and issues aren't as glaring, but there's a lot of little ones... their 3rd line leaves a lot to be desired. Their 2nd line hasn't had spectacular production. They're not really built well to withstand an injury to one of their top 2 centres. On D, if Dermott goes down they're fine. If Bogosian or Muzzin go down, they really don't have any depth in terms of what those guys bring. Their goaltending is a pretty big question mark with an incumbent #1 who's had terrible numbers and is presently injured, a backup who's amazing when he plays, but also battling injuries.
2. Stylistically, the Leafs don't seem to match up very well against teams who take a "shutdown first" approach. Their offense relies on the counterattack moreso than controlling the play.