Withey only played 207 minutes combined in his first two years at KU, but he was firmly behind guys like Aldrich, the Morris brothers, and TRob for that time. It's possible that he could have been good in those years if he had the opportunity but we never got the chance to see. Not quite comparable to Christian Braun's 1600 minutes in his first two years where he was completely mediocre.
Tyshawn Taylor definitely took a big jump in productivity in his final year, but he was honestly pretty good throughout his entire career (for instance, he was a starter on the 2010 KU team that may have been Self's best since the 2008 team):
https://www.sports-reference.com/cbb...-taylor-1.html
Malik Newman is a pretty good example as far as in-season improvement. Look how good his 2nd half was:
https://www.sports-reference.com/cbb...1/gamelog/2018