Former Portsmouth and Tottenham Hotspur boss Redknapp has gained a reputation in the past of being old-fashioned when it comes to his approach before and during games.
Wenger, on the other hand, is revered as more of a revolutionary type after changing the face of the Premier League when joining Arsenal in 1996.
Merson disputes these tags, though, telling talkSPORT: "I don't think tactically [Wenger] is as great as people say. I played under Harry Redknapp and people go, 'Oh, Harry Redknapp, a wheeler and dealer', and that is so disrespectful.
"That man was much better tactically than Arsene Wenger. I played under Arsene Wenger for just under a year and I played for Harry for a year – Harry was much better tactically."
Redknapp's last managerial job saw him take temporary charge of the Jordan national side last year, while Wenger recently passed two decades in charge of the Gunners.