I think he's going to be a pleasant surprise. As mentioned he will be insurance for us in case of injury or Dragic being traded. But he will also help us go really small like when we had success playing Lowry and Brooks together. Worst case scenario I see him as a JJ Barea type in terms of changing the pace of the game and wreaking havoc with his speed and quickness. Plus, we can put him on Barea and other under-sized pg's.
Even if he outperforms Dragic, it'd still be a difficult choice who to trade between the two. Dragic compliments Lowry to a T by being a big combo PG-SG. Flynn, however good he becomes, will be a defensive liability because of his height. It'd just be Brooks-Lowry all over again. It'd be good if he does well but I'd be looking to package him ASAP.