Teams aren't just taking on those contracts, at least not until the trade deadline when teams have more flexibility/ have a clearer idea of what the cap is next year.

Even then though you're not getting a 2nd for Allen and should be looking for more for Dvorak

Canucks decline. Can’t afford Dvorak’s contract. We’ve also already added Suter and Blueger as our bottom 6 centres, so we don’t need a guy like Dvorak anymore.

MTL ain't trading Kovacevic
You ain't getting a 2nd for Allen like already mentionned
I think MTL would have to take salary back in a Dvorak trade

If the Canucks had the capspace for Dvorak i feel like they might accept, but i am a bit higher on him than most are so take this with a grain of salt

Dvorak has become pointless after we signed Suter for a fraction of the price

How is Dvorak a defense first 3C when he’s a complete liability defensively? Canucks signed Suter for 1.6M who’s better than Dvorak. We have no interest or cap space to take on his contract

Washington, with Kuemper and Lindgren already under contract, has no use for Allen, and he'd make a tenuous cap situation even worse.