

I think it would be cool if future games would focus on unique NG+ content for those who want that veteran-level challenge, and to keep it fresh (like how DS2 planted the seeds for this). Give us a few bosses that only appear in various NG+ cycles, and another super secret and difficult boss that only appears in NG+7.
Tarzan
Animorphs game from the Animorphs website, back when the internet was new
Chess Master 5000