Last year, I thought that part of the reason our backcourt didn't seem to gel in an optimal way was that Mintz and Starling were similar players -- not that their strengths were the same, but that they were similar. Both need the ball in their hands to optimize their potential, which didn't work with them both playing out there together. And also, JJ deferred to Judah, who was more established.
Mintz couldn't shoot consistently, but excelled taking the ball into the lane and drawing fouls.
JJ shoots much better from deep than Mintz, and similarly excels at getting to the tin.
With Mintz gone, I like this change where they are making JJ the de facto lead guard -- not that he's a pure point [neither was Mintz], but given Carlos's limitations, this was a move that made sense.
It worked exceedingly well the last couple of games. JJ seems to have overcome his injury and is producing -- albeit against some of the lower rated teams in the conference. Remains to be seen whether he can maintain this level of play against the upper echelon.
But on the basis of shooting alone, I think you can make an argument that JJ is "better." I don't think he is quite as good of a ballhandler as Mintz. I think that Mintz had better hitch-up-your-shorts defensive potential than JJ, although his effort was often lacking. So, they are close, but I think JJ is a little better.