At first I did not like the trade, but the more I have thought about it, the more I like it.
it starts with KP, will he even ever come back 100% healthy ? If he does - for how long ? Seems he was always getting hurt. Even if he comes back at 100% - how good is he ? He has a rep has a great shooter, but in reality he has a mediocre shooting percentage. He is also a middling rebounder at best. Was he a star pre-injury ? Most certainly, yes - was he a superstar - a long ways to go. He rarely took over games at crunchtime. Also, between him and his brother there is a prima donna aspect. That might or might not eventually impede his court impact. Lastly, there was risk to the Knicks in his contractual situation, huge risk, when factored in with his attitude about NY.
My bottom line on KP - if he was truly all in on the Knicks re-build with a great attitude I would have liked to have kept him, but the way things are, I am happy to see him go.
Let's look at what the Knicks got in return.
Firstly - three players. Dennis Smith is a keeper. he is certainly a starting level talent with star level upside. Unless, you are sold on Mudiay (and even if you are - what about his contract ?), Dennis represents a starting caliber PG with upside. The other players are on expirings and are probably some combination of trade bait or roster fodder even though both could be solid veteran pieces on a better team.
Secondly - draft picks - the Knicks will get two #1s, one is unprotected. If any of the KP concerns rear their ugly head then Dallas will not be that good a team. The unprotected #1 could easily be a lottery pick. I believe the second # 1 is top ten protected, so there is even room for that to be a lottery pick as well. Picks could also be very valuable pieces if the Knicks want to make a serious run at trading for Anthony Davis, who is much better than is KP.
Thirdly, the Knicks get double max cap room. The key is not to squander that cap space. If they can get Durant and another legit max guy then the deal becomes massively in the Knicks favor. If they can't get the legit max guys to sign then they should find intermediate guys on short deals so they can get a legit max guy(s) later. What they can't do is to give max dollars to a less than max guy out of desperation and tie up their cap for multiple years with good, but not great players.
Actually, I think Dallas has a lot more risk in this deal than do the knicks. How KP recovers and how well he plays and if he stays healthy are all variables mostly out side of Dallas's control. The Knicks will have control over their variables, ie, who they sign with their cap space and down the road who they draft with those extra picks. They simply have to be smart to make this a good deal for them.