In a way it sort of depends on the actual question. If it's just "who will make the biggest jump", the most likely candidate is Chong. She actually regressed as the season progressed, and ended the year getting barely more PT than the walk-ons. Given that Banks is gone, Chong has a perfect chance to make an impact.
Of course, given that Tuck didn't really play next year, I'm not sure you can tag her as the one to show the biggest improvement. Additionally, she was pretty terrific when healthy, so to expect huge improvements after a year recovering from an injury (and to expect her to be that much better than when she was healthy) seems really unrealistic.
Same, in a way, goes for Stokes - she was fantastic the last quarter or so of the year. UCONN basically played 6 players and she was the only one off the bench, probably averaging close to 25 MPG towards the end.
But if the question is who shines the most, I'd say it would be a healthy Tuck or Stokes. I believe Kiah will be a starter and have high hopes for her, and a healthy Morgan will be a force. I think they will have better numbers than Saniya...