OP wrote that "Taysom was a great running QB, but still hadn't become a quality college passer during his sophomore season.", but the truth is that Taysom was never a really good college-quality passer while he was in college.

He had the athleticism and the upside and the Saints have done a good job turning him from an athlete into a QB, but his senior year (2016) he completed less than 60% with a sub 6 yard Adjusted Yards/Attempt. And he wasn't near the running threat he had been in 2013, following his multiple injuries. In 2016, he still wasn't a great passer, but he was no longer the same level of ball-carrier.