Background: Morbid Angel is an American death metal band based in Tampa, Florida formed in 1983 by guitarist and sole remaining original member Trey Azagthoth, vocalist and bassist Dallas Ward, and drummer Mike Browning. Widely considered as one of the most influential bands in the genre and important in the transition of death metal from its thrash metal roots, they were one of the first bands to incorporate guttural vocals, up-tempo blast beats, multiple tempo changes and dark atmosphere. They have been described as one of "the most influential and emulated bands in death metal", alongside Obituary and Cannibal Corpse, and have been cited as an influence by many later bands. They were also the first death metal band to experience mainstream success in connection with being signed to Giant Records in 1992, heavy rotation of their music videos on MTV, and having the music video for the song "God of Emptiness" shown on an episode of Beavis and Butt-head.
Context: 1991 saw the release of their second album, Blessed Are the Sick, which was met with widespread critical acclaim, and is considered by many to be a landmark release in the death metal genre. The album differed from its predecessor, showcasing a more "sludgy" side to the band. Following the success of Altars of Madness' and 'Blessed are the Sick', in the Spring of 1992 Morbid Angel were signed by Irving Azoff to Giant Records for one album, with the option of five more. Later that same year, second guitarist Richard Brunelle was kicked out of the band due to alleged substance abuse.  On June 22, 1993 the band released their third full-length album 'Covenant', which went on to sell over 150,000 copies in the United States alone. Their record label dedicated promotional resources to the album, and commissioned music videos for the songs 'Rapture' and 'God of Emptiness'. These music videos were put on heavy rotation by MTV, and the latter also appeared on the television show Beavis and Butt-head. The success of the album enabled the band to tour with Black Sabbath and Motorhead across the United States from February through March of 1994, which David Vincent credits with helping the band significantly expand their audience.  The band released its fourth studio album, Domination, on May 9, 1995, which featured new guitarist Erik Rutan of Ripping Corpse. It proved to be a somewhat controversial album among fans, featuring a slower, more atmospheric and experimental sound than on previous albums. Music critic describes the album's sound as "more groove-oriented". The album has gone on to sell over 100,000 copies in the United States alone. Regardless, following the release of the album their record label dropped them from their roster.
Question: Why was it controversial?

Answer:
It proved to be a somewhat controversial album among fans, featuring a slower, more atmospheric and experimental sound than on previous albums.