You obviously haven't seen Rondo's and Cousins' defense this season.
No they are not handling anybody defensively
He's not a better player, but his style of play fits better with LeBron, in my opinion.
Cousins has NEVER played excellent defense, and the last time Rondo played good defense was probably 2007/2008. Did you not see what Curry did to Rondo this season?I attribute that to Karl.
Karl never has emphasized or made defense a high principle in his coaching.
That said I know and have seen Rondo play excellent defense and the same with Cousins.
With the Cavs I think and LeBron they would be better defensively than they are now.