Baseball is so funny. The Cubs have played 9 games, which is 5.5% of the season. Some of this stuff the fans are calling for is like calling for the house of an NFL team to be cleaned late in the first quarter of Week 1.
Having said that, the bullpen is bad, was bad last year, and nothing was done to address it (sounds an awful lot like the Braves). This is on Epstein, not Maddon.
However, I also wonder if large parts of the clubhouse have tuned Maddon out. There were rumors of him leaving after last year, it's the last year on his contract, and Epstein didn't re-sign him. If they don't win the WS this year, I wonder if it is last year. I'm a big believer in the concept of coaches, especially coaches of professional teams where roster turnover is lower, having shelf lives. Even the great coaches (they just have longer shelf lives than the bad ones). Eventually your messaging, approach, demeanor, etc. get old with the players and some of them start checking out.