SK was here for "5" years. His significant improvement didn't happen till year 5 when he finally improved his dribbling enough to allow him to attack the basket and draw fouls. Again, you can't practice every single day for 4 or 5 years and play all the games without improving a little. We're talking Kenyon Martin-like, Bobby Brannen-like, Steve Logan like, Ryan Fletcher-like improvement. SK did improve in his last year and so did Justin Jackson. It's more of a big-picture general comment than specific. Most always improve some, just from the practice and games.
I understand your point L-T but here are some SK numbers.
9.7 pts FR
14.3 SO
17.0 JR
20.6 SR
He started averaging 35 minutes in his soph season through his Senior season. Would I like to see more players improving noticeably? Sure.