Your athleticism is poor. Gary Kurth is terrible. He started at 403, which isn't good, and had a 10 athleticism and a 29 speed. Even if both those were high potential he is a red-shirt that might be useful in 3 seasons. Based on his development to date, I think he was only average potential, which means a max of 30 ath and 50 speed.
You need to be signing guys that will max in the 60s and 70s in those categories (C/PF need ath, guards need 60-80 speed). Without better athletes you will never have a better team that 18-8, 16-10 type squads that get by based on IQ and skills.