I wouldn't trade Rondo for Westbrook. I think Westbrook is a pretty unattractive basketball player. A very good talent who unfortunately suffers from the Antoine Walker syndrome of thinking that he is a far, far better player than he "actually" is, or perhaps actually "should" be but never "will be" because of his head.
The problem is that he thinks he is "as important" or "as good" as Durant is. This will damage the team in OKC greatly, much as Antoine did in Boston.
Antoine Walker should have been a career 18-12 guy. Instead he thought he should be a shooter, or that he actually "could shoot"... He should have planted his butt on the box and let Pierce shoot.
Similarly, Westbrook should use all his incredible athleticism to set other players up and play defense. Shooting the basketball should be his 3rd priority.
The offensive load on that team should be shouldered and carried predominantly by Durant and Harden.
Westbrook also turns the ball over far too much.
I think OKC would be very wise to trade Westbrook for another scorer in another position and let Maynor run the point - he'll actually focus on the other players on the floor.
Maybe Al Jefferson and another player for Westbrook? Get some more scoring in the post for OKC?