Good defensive defensemen are not usually well-appreciated by the casual fan. Strong positional play, intelligent choices before a play can ever develop....the TV camera isn't usually following that guy. Usually casual fans just like a player if they make lots of hits. Jackman plays a very smart game, and brings enough physicality to be a nuisance to other teams.
I think if you polled NHL offensive players, you'd find a lot more respect for Jackman than you would if you polled random Blues chatroom fans.