Faux six-string guitar and no other instruments
Guitar Hero -- now there's a franchise I haven't given any thought in a good long while. At one point, it seemed like there would be no end to the madness. According to an account of Guitar Hero 7 shared with Kotaku, things could have gotten much worse.
In development at Vicarious Visions, the canceled game was said to be guitar-only and, in the source's words, a "disaster." The new peripheral was "Not a real guitar, or even full six-stringed. It had the classic Guitar Hero buttons on the neck with one extra new button, and six strings where the strum bar used to be."
Described as being a victim of its own ambition, the project touted dynamic venues which were unique to the song being played. The selection of music, according to the source, was "all of the worst hits from the 1990s," ultimately forming "a game that looked bad, had bad music, had very limited venues, and more was getting cut as time went on."
Personally, I got out after Guitar Hero III: Legends of Rock. That's probably for the best, because I'm lucky enough to still have mostly fond memories of the series. What about you?