Obviously, the answer is "it depends on the match ups", and also obviously, Doc has shown that he prefers to often put KG at the 5 and run with another PF, giving him a mobile unit late in games.
But if we are just talking about what WE prefer, then, JO's superior defense and ability to make free throws currently gives him the edge in my mind. IF healthy, of course.
That said, Wilcox is slowly improving in his understanding of how to play help defense behind KG and his athleticism around the hoop can be very valuable in finishing possessions.
I would consider Bass in an offensive-oriented set where we need to score points quickly and need shooters. He's still a liability on defense against some lineups, though.
In the long run, JJ may prove to be the better option over Bass for the 'KG at the 5' finishing lineup that Doc likes to use. He's still too raw, but his upside on both ends is way above Bass and he's clearly improving with each game he gets. 'Not saying it will happen before the year is out. But it would not surprise me.