The 49-year-old worked under both Wenger and Redknapp during his career, at Arsenal and Portsmouth respectively.
Although the former Tottenham Hotspur manager has a reputation as a "wheeler-dealer", Merson believes that the 70-year-old is tactically astute.
"People say [Redknapp] is a wheeler-dealer and it's so disrespectful," Merson said on panel show A League Of Their Own.
"Tactically, he's one of the best I've worked with. If Arsene Wenger had Harry Redknapp's tactical nous, Arsenal would win the league."
Redknapp was sacked as manager of Birmingham City last month with the team struggling near the bottom of the Championship table.