Chase most certainly did not get worse. His sophomore season ruined him in the eyes of most fans, rightfully so, but his last season here he was much better in terms of decision making and leadership (with a grain of salt). Honestly, I think the biggest issue with Chase was that his skill set didn't mesh well with what Legg wanted to do.
He was statistically worse in his junior year than his sophomore year. His TD/INT ratio was worse, his completion percentage was worse, his yards per attempt were worse. Plus he totally blew it toward the end of the season, so really his worst timeframe was the second half of his last year here.