Great move by Toronto. The Lowry/Derozen tandem was great for the regular season, but also a disaster in the playoffs. They will end up trading the guy with the longer contract too. If Kawhi ends up liking his time there and resigns, then it was a great deal. If Kawhi leaves after one year, it will still be a good trade because they would have dumped a max contract (Derozen) that wasn't helping them in the playoffs and also avoiding a possible luxury tax penalty in the near future.
The trade clearly makes Toronto the second best team in the East behind Boston. Toronto has a great home court advantage because of their fans, which will make them a very tough out with the addition of Kawhi. I highly doubt Kawhi resigns, but if he does, it will be because of Toronto's passionate fan base. I can also see Drake doing everything he can to help promote the Kawhi brand, and making him very marketable in a Raptors uniform.