Panoptes was a really cool boss that had the misfortune of being in an underwhelming DLC. His design was awesome and intimidating, and the fight was very cool thematically. People often ask for "single player raids". Panoptes was a single player raid boss. Add one or two more mechanics and he'd fit in with any other raid boss.
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Bungie has like some self-deprecating disorder where they get these good ideas and great artists on projects and just snatch misery from the jaws of awesomeness.