The optimist in me wants to say that Sexton has never had teammates that he could effectively work on his playmaking skills with. But this year, Garland has made huge strides in so many facets, including his ability to play off the ball, as evidenced by how often JBB runs two-PG lineups.
We don't necessarily need Collin to see the floor as well as Darius, Ricky, or Rajon do -- we just need him to, when asked, not stop the ball and let the offense flow. What he may lack as a true facilitator and playmaker he more than makes up for by being both a perimeter threat and a threat to blow by defenders that Rubio/Rondo have never been. Before his unfortunate injury this season, I think Collin was absolutely showing signs of being less of a ball-stopper.
This post is more fitting for the Sexton thread, but I want to point out that a major reason why I think Sexland can still work (I'm not advocating for them to start together) is because of the staggering improvement that Garland has shown this season.