Great deal for Dallas, which didn't have to give up anything for KP really.
The Knicks basically lose KP for Dennis Smith Jr, whom they could have drafted instead of Ntilikina two years ago anyway! On face value, it's not much for a talent like KP, but perhaps with concerns over his knee injury there wasn't much interest from other teams? If that's the case and KP did tell management he wants out, then I can understand why the Knicks decided to clear salary for a shot at next Summer's FA class, which is absolutely loaded if Leonard, Durant and Kyrie all opt out. Lets not forget that Cousins, Kemba, Butler and Thompson could also become available!
Anything could happen, but I don't think Durant signs with the Knicks unless he knows another big free agent has committed too. Even if the Knicks got Durant and Kyrie, they would still have their work cut out finding a good enough supporting cast to contend for a title.
As for Kyrie, I still think he resigns with Boston this Summer unless the Celtics flame out in the playoffs. He's on record as saying he wants to lead his own team to a title and he also very publicly told fans he wants to sign in Boston. Yes he's hit a few bumps in the road this season, but would he really give up on being the #1 guy that easily? It would be an embarrassing backflip if he decided to give up now and go back to being a sidekick for LeBron or KD! Especially when there is no guarantee the Knicks or Lakers would be any better than the Celtics!