I think he would be reluctant but what if another club wanted to trade the Leafs a top 4 D who was actually young enough they didn't need to protect him for the expansion draft? That is a unicorn. A late first is nice but someone who is young and can actually play is nicer. More realistic is to at least get a 2nd or 3rd back in a larger deal.
For the right player it means valuable stuff has to be on the table so if you don't want to deal the 1st, or Robertson, or Liljegren/Sandin then what is there that gets anything special back? I think they hit very well with Robertson and Sandin. It depends on who they can get but the window is now and they haven't even added these two to the mix. A late 1st isn't an issue on a club with the kind of young talent.