If the Leafs could easily dispose of Horton, they would have done so already.
Then it's clear you'll have to pony up some assets to get someone to take Horton. I don't see it being us.
Weber was just named captain. I doubt the Habs are doing a rebuild.
I think the price of moving bad contracts is overstated. In 2/3 cases I can think of the cost being quite low and 1 being high.
Low:
Filppula - Basically cost the Lightning a 7th to move
Beleskey - Was used in the deal to land Nash, NYR didn't need to take a cap dump to get good value for Nash IMO, they could have gotten a 1st+prospect anyway
High:
Bolland - At the time, a recent 10th-11th overall pick in Crouse to move that contract seemed high.
In terms of who it has to be? Montreal or the Rangers need to be the people taking the Horton contract, it's the standard LTR thing where it shouldn't hurt either team that isn't really going to be competing but the problem is the dollars are real. Only Montreal and the New York Rangers are able to pay out that type of salary for a player like Horton.