If Lillard decided he wanted to take 20 shots/game, he could easily be ranked among some of the
really great scoring combo/point guards in recent years. There's nothing keeping him from taking more shots. Double teaming him out on the perimeter is a recipe for disaster as the Lakers found, because once he inevitably breaks that down you don't have anything left at the rim. Put a bigger guard on him and he'll go around him, so they have to back off a little and risk the three pointer. He can pretty much create a quality shot for himself whenever he wants, so why not do it more? It means fewer touches for Aldridge, but then that also means fewer 18 foot jumpers and more offensive putbacks.
When you see him go off for crazy fourth quarters like last night, you can't help but wonder if maybe he should really do that all the time and go after a scoring title. Teams with guys leading the NBA in scoring tend to be contenders. Let LMA/Wes/Batum focus more on being just opportunistic scorers.
The biggest argument against that, I suppose, is TS%. Dame has by far the best among the list I linked to, and it's not even close. Do you sacrifice that to create a marquis player, a true top 3 superstar?