Complex sentence: Warner Brothers had looked into the possibility of casting characters with persons other than their original actors for at least one character (Galen), however, this had met with extreme criticism from "Babylon 5" fans.
Split into simpler sentences: Warner Brothers had looked into the possibility of casting characters with persons other than their original actors for at least one character (Galen). The suggestion of recasting was met with extreme criticism from "Babylon 5" fans.