I think what people are saying is that Wade, Rose, and Crowder should have been able to make up for a decent portion of what they lost in Kyrie. And, since Kyrie was apparently not much of a defender in seasons past, the lack of D from Wade and Rose shouldn't really matter.
Basically, what seems to have happened here, is that Kyrie was considerably more important than he was given credit for. I understand that the addition of IT will help, but the damage should be mitigated with the [free] additions of Wade, Rose, and Crowder.
I will hold off my judgment for another 10-15 games, though - it is still way too early in the season.