Toronto seems stacked at forward (with lots of high end young talent) and not so much on D. The defense is ok, but I'm not sure if its Cup caliber. Bottom line, the roster is imbalanced - opposite of the ducks who are loaded on D.
I don't mean this to troll, but my question is how exactly is Toronto expecting to get a top 3 defenseman without trading Marner or Nylander (or perhaps Kadri)? Is there a high end defensive prospect in the pipeline who will be a solid contributor in the current window? A package of picks and role players is not likely to get top 3 D-man with term at a great cost (Manson).
I suppose free agency is an option - but not many top d-men make it to free agency and then the salary may not be compatible with keeping Tavares, Nylander, Matthews, Marner and Kadri. If Gardiner walks, that saves $$ but opens another hole. If he stays, that is more salary cap pressure.
A player like Manson (great contract and checks all the boxes on the ice) is the kind of guy they eventually will have to acquire unless Toronto trades for rentals each year (i.e., high draft picks). And it seems Nylander/Marner (or maybe Kadri) would need to be in the deal to get a Manson like player.
And just to be clear, I think the ducks will be in re-tool mode soon and MAY need to trade a player like Manson or Montour to get high end forward talent. That decision is probably a year away - once the need to retool becomes clearer and the ducks have a better projection for the current prospects (both defensemen like Larsson who might replace Manson/Montour and forward talent like Sam Steel). But the ducks won't trade Manson/Montour unless the return is a top level player.