Judge Death wrote:
The best SW films were the ones Lucas seemed to have the least control over...
I'm not sure I'd put it that way. He did have control over TESB and ROTJ; it's just that back then he hadn't yet been spoiled by decades of power and insularity and had the good sense to collaborate with others instead of believing he could make all the decisions unilaterally. (Even on the original film, Gary Kurtz contributed far more to the process than he's officially given credit for.)
If anything, I'd say that on the prequels (and Indy 4), he lacked sufficient control over himself
, because he no longer had the judgment to realize his limitations and share responsibility with others.