Point guards and big men traditionally take longer to figure it out at the NBA level. I see no roadblocks to Davion's continued development. He's borderline untradable at this point not because he's a star (obviously not), but because it's not wise to cash out on players as they are making big strides.
Petrie had exquisite timing in trading away players at the peak/end of their major contributing years.
I expect a massive jump from Davion next year. Bobby Jackson type off the bench is completely within reach, and soon.