I think scoring isn't Westbrook's strong suit. Nevertheless, his ability to grab a lot of rebounds and make a lot of assists can be very useful for the Lakers, but only in those moments when Russ makes the minimum number of turnovers per game. As for Davis' absence, Thomas Bryant might partially replace him if he continues to perform as well as he did in the previous game against the Nuggets.
I barely see Westbrook create more than 20 points lately since he is now in the second unit. His best contributions are from his assists and rebounds. This is good since he keeps feeding Lebron and AD or anyone who is hot in the Lakers to keep them hot.
Even if Westbrook is not a scoring machine anymore and barely create 20+ points, he's still one of the huge reasons why the Lakers got an improvement lately. Yes, it did start when he fully embraced his role as the 6th man and trusted coach Ham's decision that he's more valuable coming from the 2nd unit. Also, coach Ham started utilizing the former Wizards, Thomas Bryant as their center while Davis is having some issues and the results were better because they aren't that much having a hard time when Davis is not around.