Strickland (or somebody, but I'm pretty sure it was him) had a few posts last spring about how atrocious Jones was offensively last season. I don't have time to dig them up, but maybe somebody else will.
I tend to believe Lewis' scoring numbers and shooting percentages this year are more a function of having no help inside than anything else. Jones can't shoot the ball. Period. There is not a team in the country, including UK, KU, or dook, on which he would be able to shoot the ball effectively. Lewis, on the other hand, had a pretty solid stretch (small sample size alert) against Miami/Duke/Clemson/GT last season when he filled in for Brown. Jones could have accumulated all the minutes he wanted last year- Miller-McIntyre didn't have a particularly good season, especially as a PG, so Jones could have taken that position if he was capable. Lewis, on the other hand, was playing behind a 2nd round pick.
In the end, they put up similar stats with Jones playing 6 minutes a game more than Lewis. And maybe you watched more state games than I did last year (although I doubt it), but in the big games, I did not see Lewis getting abused defensively. He's never going to be all-defense, but he isn't a complete sieve either. I also tend to think Lewis' offensive skills offset his defensive shortcomings, while Jones' offensive shortcomings offset his defensive skills. But YMMV.