Original sentence: Following its release, Smith departed from Iron Maiden in 1990, and was replaced by Janick Gers.It is widely believed that Adrian left due to his unhappiness with the direction the band was taking: after releasing the experimental Somewhere in Time and Seventh Son of a Seventh Son albums, Steve Harris had decided to take the band back to a more traditional hard rock direction which you can clearly hear on the No Prayer for the Dying album
Edited sentence: Following its release, Smith departed from Iron Maiden in 1990 thus it began the band's decline.It is widely believed that Adrian left due to his unhappiness with the direction the band was taking : after releasing the experimental Somewhere in Time and Seventh Son of a Seventh Son albums, Steve Harris had decided to take the band back to a more traditional hard rock direction which you can clearly hear on the No Prayer for the Dying album