Why Toronto does it?
Adds 2 of their most significant needs in 1 deal this offseason - a top 4 defender and a middle 6 centre. Roy offers something the Leafs don’t have at all in their system, which is a right handed centre. With Tavares’ slow decline a new centre is needed and Roy would slide in perfectly to a middle 6 role that could see some 2C time. Hague is everything Treliving loves in a defender - he’s big, mobile, physical, long reach, two way player , and a great leader. He’s be the perfect fit long term for this team.

Why Toronto doesn’t do it?
This is a high price for a team that has the farm system starting to deplete. Robertson has begun to turn heads in to organization as a solid offensive contributor with a good work ethic that may be important to keep while he’s cheap.

Why Vegas does it?
Cap space. After signing Robertson to a new contract, this likely saves them at least $3.5M in cap space for next season. With their impending cap crunch, they’ll need to shed salary and look to bring in younger players that can produce - Robertson has started to show his offensive potential with a 20 goal pace season with limited offensive time. He could slide into Vegas’ top 9 and potentially top 6 immediately. Losing Roy and Hague likely aren’t ideal, but with Roy being paid $3M for a 4th line role and Hague likely due for a raise in 1 season, this would allow more cap to not only bring back 1 of Stephenson or Marchessault but also re-sign Theodore.

Why Vegas doesn’t do it?
Robertson still being injury concerns and even though he’s stayed healthy this season, it’s still a concern. There will be a market for both these players and maybe they feel like they can be better value trading them separately. I’m not sure I can see Vegas really selling off players as they never really have to date, but with the cap structure it may be time.