That's not good, KD already had Irving and if he comes back playing his old self, they had a chance to win championships.
KD leave Warriors because he don't want to play with a superteam, he wanted to prove again in another team and Him and Irving are like Lebron and Irving in the Cleveland days and I think Durant is even better.
They could team up to get another ring, but we need to see the full damage of his injury first and see if he can comeback just like his old self. KD leaves the Warriors because he was chasing for his ring and now that he accomplished it, time for him to move and partner with other elite players like Irving. It could be Irving and Lebron again, but it is too early to call as KD needs to recovery physically and mentally after that devastating injury.