I agree with you, but I think that you're really talking about ball dominant scorers, rather than shoot first point guards.
Rose's Bulls got stifled in the playoffs not because he was the point, but because the Heat could throw LeBron on him. Carmelo's suffered the same way since he came to the Knicks. We saw Durant go through the same thing in the playoffs last year without Westbrook--which is why I'd argue that, if the Thunder are going to go all the way, they need both of those guys.