Again, there is no 1st round pick that Kuemper can get. Arizona needs to realize that if they want a 1st round pick, OEL is going to be the only guy that gets them one, and it's going to mean they're either taking salary back or retaining. The ship where they get that without a 7-year retention may have sailed with Vancouver getting Schmidt.
There's just no market for goalies, and certainly not in a context where one of the primary objectives is reducing $ spent. Heck, look at the Matt Murray trade, and the only reason that the Pens were able to get that is because Ottawa had like 4 2nd rounders, and felt that Murray was going to be their goalie of the future. Kuemper is an immediate fix.
The Leafs get a different (not better, but likely worse) goalie -- one who's more accustomed to playing a tandem; and a little bit of cap savings / an extra year of cost certainty.
The Canes get a substantial upgrade and a true #1 goalie, as they've been trying to get/develop one for years, it costs them a 2nd round pick and $200k.
The Coyotes get a 2nd round pick (likely close to Kuemper's true market value), plus a super cheap tandem goalie, and one of Reimer/Raanta may be tradable at the deadline if you want to throw Hill into the tandem for the remainder of the season.