This is a great move for Spurs. Just replaced a disgruntled player that hasn't played for you in basically 2 seasons for a perennial all star scorer. Derozan has warts but any reason to think that Pop can't make him better in that system?
For Toronto, it's basically one more swing at a finals run and pray they can somehow convince Kawhi. Otherwise, it will be a firesale/rebuild in their near future.