I do wish Rondo was more consistent, but his inconsistency is massively overstated in the media and by fans. Rondo is not radically more inconsistent than other star players in the league; it is just "easier" to see when he has an off game because he isn't a scorer.
When Lebron or Kobe has an off game, they still score 15-20 points (because they huck up 20+ shots). Rondo doesn't score much anyway, and he is also smart enough not to keep shooting when he is having an off night, so he ends up scoring 7 points on 5 shots. To the casual observer, it "looks" like a worse game (even though Kobe going, for example, 10-25 is significantly worse for the team, even if he scores 20 points).