Ryan Walters is no stranger to second-year improvement. As a defensive coordinator, it’s his history-proven expectation.  In 2018, during Walters’ first season as the defensive coordinator at Missouri, the Tigers allowed 25.46 points and 388.5 total yards per game. During his second season in charge, Missouri gave up just 19.42 points and 312 total yards per game.  The trends continued at Illinois. Walters’ Fighting Illini defense surrendered 21.92 points and 365.5 total yards per game in 2021. Just a year later — as one of the top defenses in the country in 2022 — Illinois allowed just 12.77 points and 273.5 total yards per game. Walters, now entering his second season at Washington, has a group that seems primed for a similar jump. UW boasts one of the country’s most experienced linebacker corps.…