I mean with songs like David Bowie Space Oddity, Warren Zevon Werewolf of London & who could forget John Lennon Imagine. Its heavily Keys oriented. But thats not a bad thing because its a gimmick, Pro Guitar, Bass & Drums. Although its more, lets say helpful to the experience of making you feel like youre actually playing instruments instead of plastic.
Space Oddity is not key-centric at all, it has 2 guitar solos ffs. If they wanted a keys Bowie song, they would have went with 'Life On Mars' or 'Changes'.
'Imagine' and 'Bohemian Rhapsody' are definitely key-centric songs, but they're both also huge and popular hits, while Bohemian Rhapsody is also there for the insane harmonies (not to mention most of Queen's other big songs were already released as DLC at this point).